Setup

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Results

All values are z-scored

Final Major mean + std

Tier 1 Drop mean + std

Final Major mean * std

Tier 1 Drop mean * std

Final Major mean * std B/W

Tier 1 Drop mean * std B/W

## Takeaway from the GLMs

It seems that the main signal is coming from alpha minus and tier_1_drop_to_zero.

GLMs

Outcome ~ Alpha_minus

alpha_minus_mean_2a1b indirectly proportional to tier_1_drop_to_zero.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.44403    0.08793 -16.423   <2e-16 ***
## alpha_minus_mean_2a1b -0.23629    0.09671  -2.443   0.0146 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 837.93  on 852  degrees of freedom
## Residual deviance: 831.54  on 851  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 835.54
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)
## (Intercept)            0.04925    0.06850   0.719    0.472
## alpha_minus_mean_2a1b -0.01440    0.06855  -0.210    0.834
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1182.0  on 852  degrees of freedom
## Residual deviance: 1181.9  on 851  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1185.9
## 
## Number of Fisher Scoring iterations: 3
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

FM ~ alpha minus/plus mean + alpha minus/plus std + beta mean + beta std

alpha_minus_std_2a1b directly proportional to final major

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)  
## (Intercept)            0.09982    0.10027   0.996   0.3195  
## alpha_minus_mean_2a1b  0.11122    0.10168   1.094   0.2740  
## alpha_minus_std_2a1b   0.22613    0.12547   1.802   0.0715 .
## alpha_plus_std_2a1b   -0.04829    0.14417  -0.335   0.7377  
## alpha_plus_mean_2a1b   0.09183    0.15719   0.584   0.5591  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 724.43  on 525  degrees of freedom
## Residual deviance: 719.07  on 521  degrees of freedom
##   (349 observations deleted due to missingness)
## AIC: 729.07
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b  + alpha_minus_std_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)   
## (Intercept)            0.04902    0.06892   0.711  0.47696   
## alpha_minus_mean_2a1b -0.02524    0.10087  -0.250  0.80239   
## alpha_minus_std_2a1b   0.26056    0.08693   2.997  0.00272 **
## beta_2a_mean_2a1b      0.02642    0.10209   0.259  0.79579   
## beta_2a1b_std         -0.12220    0.09055  -1.350  0.17716   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1182.0  on 852  degrees of freedom
## Residual deviance: 1171.7  on 848  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1181.7
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)  
## (Intercept)            0.10017    0.10133   0.989   0.3229  
## alpha_minus_mean_2a1b  0.13398    0.16325   0.821   0.4118  
## alpha_minus_std_2a1b   0.25991    0.15053   1.727   0.0842 .
## alpha_plus_std_2a1b   -0.02356    0.14801  -0.159   0.8735  
## alpha_plus_mean_2a1b   0.12252    0.16121   0.760   0.4472  
## beta_2a_mean_2a1b     -0.13734    0.15302  -0.898   0.3694  
## beta_2a1b_std         -0.14641    0.12192  -1.201   0.2298  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 724.43  on 525  degrees of freedom
## Residual deviance: 715.86  on 519  degrees of freedom
##   (349 observations deleted due to missingness)
## AIC: 729.86
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

### DTZ ~ alpha minus/plus mean + alpha minus/plus std + beta mean + beta std

alpha_minus_mean_2a1b and alpha_minus_std_2a1b are both indirectly proportional to DTZ when beta is in the model, but not when alpha_plus is

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.56782    0.13116 -11.954   <2e-16 ***
## alpha_minus_mean_2a1b -0.28409    0.14519  -1.957   0.0504 .  
## alpha_minus_std_2a1b  -0.08122    0.16640  -0.488   0.6255    
## alpha_plus_std_2a1b    0.18151    0.21199   0.856   0.3919    
## alpha_plus_mean_2a1b   0.11600    0.22052   0.526   0.5989    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 475.06  on 525  degrees of freedom
## Residual deviance: 470.00  on 521  degrees of freedom
##   (349 observations deleted due to missingness)
## AIC: 480
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b  + alpha_minus_std_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.45394    0.08856 -16.418   <2e-16 ***
## alpha_minus_mean_2a1b -0.24031    0.11791  -2.038   0.0415 *  
## alpha_minus_std_2a1b  -0.21281    0.10491  -2.029   0.0425 *  
## beta_2a_mean_2a1b     -0.05904    0.12087  -0.488   0.6252    
## beta_2a1b_std         -0.04274    0.10849  -0.394   0.6936    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 837.93  on 852  degrees of freedom
## Residual deviance: 825.40  on 848  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 835.4
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.55814    0.13165 -11.836   <2e-16 ***
## alpha_minus_mean_2a1b -0.21041    0.18937  -1.111    0.267    
## alpha_minus_std_2a1b  -0.15143    0.20244  -0.748    0.454    
## alpha_plus_std_2a1b    0.17239    0.21722   0.794    0.427    
## alpha_plus_mean_2a1b   0.14628    0.24493   0.597    0.550    
## beta_2a_mean_2a1b     -0.09219    0.18083  -0.510    0.610    
## beta_2a1b_std          0.06898    0.15430   0.447    0.655    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 475.06  on 525  degrees of freedom
## Residual deviance: 469.61  on 519  degrees of freedom
##   (349 observations deleted due to missingness)
## AIC: 483.61
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

FM ~ alpha minus mean * alpha plus mean + semester study

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_plus_mean_2a1b * alpha_minus_mean_2a1b + semester_study + UM_credits_at_study", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                                             Estimate Std. Error z value
## (Intercept)                                 0.971162   0.183348   5.297
## alpha_plus_mean_2a1b                        0.085771   0.108074   0.794
## alpha_minus_mean_2a1b                       0.105763   0.101373   1.043
## semester_study                             -0.478161   0.352205  -1.358
## UM_credits_at_study                         0.002324   0.022886   0.102
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b  0.134139   0.115508   1.161
##                                            Pr(>|z|)    
## (Intercept)                                1.18e-07 ***
## alpha_plus_mean_2a1b                          0.427    
## alpha_minus_mean_2a1b                         0.297    
## semester_study                                0.175    
## UM_credits_at_study                           0.919    
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b    0.246    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 724.43  on 525  degrees of freedom
## Residual deviance: 695.46  on 520  degrees of freedom
##   (349 observations deleted due to missingness)
## AIC: 707.46
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_plus_mean_2a0b * alpha_minus_mean_2a0b + semester_study + UM_credits_at_study", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                                            Estimate Std. Error z value Pr(>|z|)
## (Intercept)                                 0.94291    0.18294   5.154 2.55e-07
## alpha_plus_mean_2a0b                       -0.02541    0.09843  -0.258    0.796
## alpha_minus_mean_2a0b                       0.10737    0.11522   0.932    0.351
## semester_study                             -0.47497    0.35367  -1.343    0.179
## UM_credits_at_study                         0.00184    0.02299   0.080    0.936
## alpha_plus_mean_2a0b:alpha_minus_mean_2a0b -0.10681    0.08900  -1.200    0.230
##                                               
## (Intercept)                                ***
## alpha_plus_mean_2a0b                          
## alpha_minus_mean_2a0b                         
## semester_study                                
## UM_credits_at_study                           
## alpha_plus_mean_2a0b:alpha_minus_mean_2a0b    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 724.43  on 525  degrees of freedom
## Residual deviance: 695.63  on 520  degrees of freedom
##   (349 observations deleted due to missingness)
## AIC: 707.63
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a0b
##   [all]"` to get smooth plots.

DTZ ~ alpha minus mean * alpha plus mean + semester study

Alpha minus is indirectly proportional to dropout but semester study is directly proportional.

That’s a weird finding, it means the later they participate the likelier they are to drop… Interesting.

This seems to be begging for a survival model, may do a survival model towards the end of this markdown

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_plus_mean_2a1b * alpha_minus_mean_2a1b + semester_study + UM_credits_at_study", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                                            Estimate Std. Error z value Pr(>|z|)
## (Intercept)                                -1.40492    0.23003  -6.107 1.01e-09
## alpha_plus_mean_2a1b                       -0.06856    0.14683  -0.467  0.64055
## alpha_minus_mean_2a1b                      -0.31947    0.14930  -2.140  0.03237
## semester_study                              1.06637    0.40075   2.661  0.00779
## UM_credits_at_study                        -0.07773    0.02767  -2.809  0.00497
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b  0.24106    0.26350   0.915  0.36027
##                                               
## (Intercept)                                ***
## alpha_plus_mean_2a1b                          
## alpha_minus_mean_2a1b                      *  
## semester_study                             ** 
## UM_credits_at_study                        ** 
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 475.06  on 525  degrees of freedom
## Residual deviance: 462.65  on 520  degrees of freedom
##   (349 observations deleted due to missingness)
## AIC: 474.65
## 
## Number of Fisher Scoring iterations: 5
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_mean_1a1b + semester_study + UM_credits_at_study", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                     Estimate Std. Error z value Pr(>|z|)    
## (Intercept)         -1.33762    0.17095  -7.825 5.09e-15 ***
## alpha_mean_1a1b     -0.21066    0.10806  -1.949 0.051251 .  
## semester_study       1.00222    0.27223   3.682 0.000232 ***
## UM_credits_at_study -0.07254    0.01908  -3.802 0.000144 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 850.16  on 874  degrees of freedom
## Residual deviance: 831.54  on 871  degrees of freedom
## AIC: 839.54
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_mean_1a1b [all]"`
##   to get smooth plots.

FM ~ alpha_minus mean +/* std (base model)

interestingly the SD of alpha_minus seems to be predictive of final major across a few of these models.

Seems to be a consistent finding

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_std_2a1b + alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)   
## (Intercept)            0.04891    0.06884   0.711  0.47737   
## alpha_minus_std_2a1b   0.20488    0.07191   2.849  0.00438 **
## alpha_minus_mean_2a1b  0.03437    0.07165   0.480  0.63144   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1182.0  on 852  degrees of freedom
## Residual deviance: 1173.7  on 850  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1179.7
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_std_2a1b * alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                                              Estimate Std. Error z value
## (Intercept)                                 0.0434589  0.0697994   0.623
## alpha_minus_std_2a1b                        0.2161975  0.0759182   2.848
## alpha_minus_mean_2a1b                       0.0001792  0.1012390   0.002
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b -0.0224746  0.0469709  -0.478
##                                            Pr(>|z|)   
## (Intercept)                                  0.5335   
## alpha_minus_std_2a1b                         0.0044 **
## alpha_minus_mean_2a1b                        0.9986   
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b   0.6323   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1182.0  on 852  degrees of freedom
## Residual deviance: 1173.4  on 849  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1181.4
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

DTZ ~ alpha_minus mean +/* std (base model)

This is fascinating, because both are significant to predicting dropout.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_std_2a1b + alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.45255    0.08840 -16.431  < 2e-16 ***
## alpha_minus_std_2a1b  -0.21028    0.08656  -2.429  0.01513 *  
## alpha_minus_mean_2a1b -0.25574    0.09102  -2.810  0.00496 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 837.93  on 852  degrees of freedom
## Residual deviance: 825.84  on 850  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 831.84
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_std_2a1b * alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                                             Estimate Std. Error z value
## (Intercept)                                -1.455100   0.090124 -16.146
## alpha_minus_std_2a1b                       -0.207344   0.088711  -2.337
## alpha_minus_mean_2a1b                      -0.269848   0.131479  -2.052
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b -0.009447   0.063182  -0.150
##                                            Pr(>|z|)    
## (Intercept)                                  <2e-16 ***
## alpha_minus_std_2a1b                         0.0194 *  
## alpha_minus_mean_2a1b                        0.0401 *  
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b   0.8811    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 837.93  on 852  degrees of freedom
## Residual deviance: 825.82  on 849  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 833.82
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

FM ~ alpha_minus mean + std (1a1b)

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_std_1a1b + alpha_mean_1a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                  Estimate Std. Error z value Pr(>|z|)
## (Intercept)      0.075856   0.067724   1.120    0.263
## alpha_std_1a1b  -0.002825   0.115080  -0.025    0.980
## alpha_mean_1a1b  0.084949   0.118464   0.717    0.473
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1211.8  on 874  degrees of freedom
## Residual deviance: 1210.2  on 872  degrees of freedom
## AIC: 1216.2
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_mean_1a1b [all]"`
##   to get smooth plots.

### DTZ ~ alpha_minus mean + std (1a1b)

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_std_1a1b + alpha_mean_1a1b", 
##     family = binomial, data = jrk_ABG)
## 
## Coefficients:
##                 Estimate Std. Error z value Pr(>|z|)    
## (Intercept)     -1.47311    0.08791 -16.757   <2e-16 ***
## alpha_std_1a1b   0.32105    0.17578   1.826   0.0678 .  
## alpha_mean_1a1b  0.05978    0.18571   0.322   0.7475    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 850.16  on 874  degrees of freedom
## Residual deviance: 842.45  on 872  degrees of freedom
## AIC: 848.45
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_mean_1a1b [all]"`
##   to get smooth plots.

Extra Visualizations

n_negative updates

## `geom_smooth()` using formula = 'y ~ x'

n_positive updates

## `geom_smooth()` using formula = 'y ~ x'

n_any updates

## Warning: Groups with fewer than two datapoints have been dropped.
## ℹ Set `drop = FALSE` to consider such groups for position adjustment purposes.
## Groups with fewer than two datapoints have been dropped.
## ℹ Set `drop = FALSE` to consider such groups for position adjustment purposes.
## `geom_smooth()` using formula = 'y ~ x'

Follow-Up 1: Range Restriction

So it seems that a lot of these a large amount of variance in the higher ends of alpha_minus_mean. SO like we do for the predictions analyses, it may be good to restrict the range.

quantile(jrk_ABG$alpha_minus_mean_2a1b, na.rm = TRUE, probs = c(0, 0.20, 0.25, 0.40, 0.5, 0.6, 0.75, 0.8, 1))
##          0%         20%         25%         40%         50%         60% 
## -5.31359627 -0.59059656 -0.45741075 -0.12954038 -0.03473533  0.01142524 
##         75%         80%        100% 
##  0.27383032  0.42705393  9.01566152
ggplot(jrk_ABG, aes(x = "", y = abs(alpha_minus_mean_2a1b))) +
  geom_violin(fill = "skyblue", color = "black") +
  geom_boxplot(width = 0.1, fill = "white", outlier.shape = NA) +
  geom_hline(yintercept = 2, color = "black", linetype = "dashed") +
  # geom_hline(yintercept = -2, color = "black", linetype = "dashed") +
  labs(
    x = NULL,
    y = "alpha_minus_mean_2a1b",
    title = "Violin Plot of |alpha_minus_mean_2a1b| with Boxplot"
  ) +
  theme_minimal()
## Warning: Removed 22 rows containing non-finite outside the scale range
## (`stat_ydensity()`).
## Warning: Removed 22 rows containing non-finite outside the scale range
## (`stat_boxplot()`).

pct <- mean(abs(jrk_ABG$alpha_minus_mean_2a1b) <= 2, na.rm = TRUE) * 100

paste0(pct, "% of the data falls between -2 and 2")
## [1] "95.5451348182884% of the data falls between -2 and 2"

Kind of arbitrary but I’m going to pick to restrict the range to -2 <= x <= 2 (remember this is in standard deviations, so this is keeping anything within 2 standard deviations)

jrk_ABG_RR <- jrk_ABG[abs(jrk_ABG$alpha_minus_mean_2a1b) <= 2,]

Outcome ~ Alpha_minus

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.42853    0.09008 -15.858   <2e-16 ***
## alpha_minus_mean_2a1b -0.25237    0.12897  -1.957   0.0504 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 810.08  on 814  degrees of freedom
## Residual deviance: 806.20  on 813  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 810.2
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)
## (Intercept)            0.03663    0.07044   0.520    0.603
## alpha_minus_mean_2a1b  0.06749    0.10099   0.668    0.504
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1129.6  on 814  degrees of freedom
## Residual deviance: 1129.2  on 813  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1133.2
## 
## Number of Fisher Scoring iterations: 3
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

FM ~ alpha minus/plus mean + alpha minus/plus std + beta mean + beta std

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)  
## (Intercept)            0.03939    0.11023   0.357    0.721  
## alpha_minus_mean_2a1b  0.06691    0.15556   0.430    0.667  
## alpha_minus_std_2a1b   0.34657    0.15134   2.290    0.022 *
## alpha_plus_std_2a1b   -0.05376    0.14670  -0.366    0.714  
## alpha_plus_mean_2a1b   0.07809    0.15811   0.494    0.621  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 699.70  on 507  degrees of freedom
## Residual deviance: 692.61  on 503  degrees of freedom
##   (329 observations deleted due to missingness)
## AIC: 702.61
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b  + alpha_minus_std_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                        Estimate Std. Error z value Pr(>|z|)    
## (Intercept)            0.009755   0.071679   0.136 0.891746    
## alpha_minus_mean_2a1b  0.165777   0.138485   1.197 0.231277    
## alpha_minus_std_2a1b   0.312410   0.091599   3.411 0.000648 ***
## beta_2a_mean_2a1b     -0.125479   0.116968  -1.073 0.283374    
## beta_2a1b_std         -0.083629   0.093502  -0.894 0.371104    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1129.6  on 814  degrees of freedom
## Residual deviance: 1112.7  on 810  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1122.7
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)  
## (Intercept)            0.03042    0.11079   0.275   0.7837  
## alpha_minus_mean_2a1b  0.28107    0.22994   1.222   0.2216  
## alpha_minus_std_2a1b   0.32807    0.16668   1.968   0.0490 *
## alpha_plus_std_2a1b   -0.05041    0.15492  -0.325   0.7449  
## alpha_plus_mean_2a1b   0.16471    0.16933   0.973   0.3307  
## beta_2a_mean_2a1b     -0.30164    0.17389  -1.735   0.0828 .
## beta_2a1b_std         -0.05621    0.12235  -0.459   0.6459  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 699.70  on 507  degrees of freedom
## Residual deviance: 688.35  on 501  degrees of freedom
##   (329 observations deleted due to missingness)
## AIC: 702.35
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

### DTZ ~ alpha minus/plus mean + alpha minus/plus std + beta mean + beta std

alpha_minus_mean_2a1b and alpha_minus_std_2a1b are both indirectly proportional to DTZ when beta is in the model, but not when alpha_plus is

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)            -1.4496     0.1357 -10.680   <2e-16 ***
## alpha_minus_mean_2a1b  -0.2640     0.1986  -1.329    0.184    
## alpha_minus_std_2a1b   -0.3020     0.1863  -1.621    0.105    
## alpha_plus_std_2a1b     0.1906     0.2114   0.901    0.367    
## alpha_plus_mean_2a1b    0.1176     0.2205   0.533    0.594    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 468.34  on 507  degrees of freedom
## Residual deviance: 462.83  on 503  degrees of freedom
##   (329 observations deleted due to missingness)
## AIC: 472.83
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b  + alpha_minus_std_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.42253    0.09053 -15.714   <2e-16 ***
## alpha_minus_mean_2a1b -0.32180    0.15824  -2.034    0.042 *  
## alpha_minus_std_2a1b  -0.23671    0.10410  -2.274    0.023 *  
## beta_2a_mean_2a1b      0.02713    0.12944   0.210    0.834    
## beta_2a1b_std         -0.09438    0.10461  -0.902    0.367    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 810.08  on 814  degrees of freedom
## Residual deviance: 797.13  on 810  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 807.13
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_mean_2a1b + alpha_minus_std_2a1b + alpha_plus_std_2a1b + alpha_plus_mean_2a1b + beta_2a_mean_2a1b + beta_2a1b_std", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                        Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.447963   0.135924 -10.653   <2e-16 ***
## alpha_minus_mean_2a1b -0.358743   0.281574  -1.274    0.203    
## alpha_minus_std_2a1b  -0.281879   0.207384  -1.359    0.174    
## alpha_plus_std_2a1b    0.191710   0.210086   0.913    0.361    
## alpha_plus_mean_2a1b   0.074501   0.221684   0.336    0.737    
## beta_2a_mean_2a1b      0.120897   0.213430   0.566    0.571    
## beta_2a1b_std          0.001104   0.155788   0.007    0.994    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 468.34  on 507  degrees of freedom
## Residual deviance: 462.48  on 501  degrees of freedom
##   (329 observations deleted due to missingness)
## AIC: 476.48
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

FM ~ alpha minus mean * alpha plus mean + semester study

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_plus_mean_2a1b * alpha_minus_mean_2a1b + semester_study + UM_credits_at_study", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                                            Estimate Std. Error z value Pr(>|z|)
## (Intercept)                                 1.01824    0.18722   5.439 5.36e-08
## alpha_plus_mean_2a1b                        0.09013    0.10933   0.824   0.4097
## alpha_minus_mean_2a1b                       0.10332    0.15975   0.647   0.5178
## semester_study                             -0.69888    0.40526  -1.725   0.0846
## UM_credits_at_study                         0.01496    0.02619   0.571   0.5677
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b  0.08032    0.18360   0.437   0.6618
##                                               
## (Intercept)                                ***
## alpha_plus_mean_2a1b                          
## alpha_minus_mean_2a1b                         
## semester_study                             .  
## UM_credits_at_study                           
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 699.70  on 507  degrees of freedom
## Residual deviance: 668.59  on 502  degrees of freedom
##   (329 observations deleted due to missingness)
## AIC: 680.59
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_plus_mean_2a0b * alpha_minus_mean_2a0b + semester_study + UM_credits_at_study", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                                            Estimate Std. Error z value Pr(>|z|)
## (Intercept)                                 1.01240    0.18743   5.401 6.61e-08
## alpha_plus_mean_2a0b                       -0.01385    0.10323  -0.134   0.8933
## alpha_minus_mean_2a0b                       0.16829    0.16040   1.049   0.2941
## semester_study                             -0.68128    0.40863  -1.667   0.0955
## UM_credits_at_study                         0.01285    0.02641   0.487   0.6266
## alpha_plus_mean_2a0b:alpha_minus_mean_2a0b -0.13141    0.09572  -1.373   0.1698
##                                               
## (Intercept)                                ***
## alpha_plus_mean_2a0b                          
## alpha_minus_mean_2a0b                         
## semester_study                             .  
## UM_credits_at_study                           
## alpha_plus_mean_2a0b:alpha_minus_mean_2a0b    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 699.70  on 507  degrees of freedom
## Residual deviance: 666.14  on 502  degrees of freedom
##   (329 observations deleted due to missingness)
## AIC: 678.14
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a0b
##   [all]"` to get smooth plots.

DTZ ~ alpha minus mean * alpha plus mean + semester study

Alpha minus is no longer significant semester study is directly proportional.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_plus_mean_2a1b * alpha_minus_mean_2a1b + semester_study + UM_credits_at_study", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                                            Estimate Std. Error z value Pr(>|z|)
## (Intercept)                                -1.32120    0.23201  -5.695 1.24e-08
## alpha_plus_mean_2a1b                       -0.07712    0.14662  -0.526  0.59891
## alpha_minus_mean_2a1b                      -0.32484    0.21082  -1.541  0.12336
## semester_study                              1.37598    0.44544   3.089  0.00201
## UM_credits_at_study                        -0.10020    0.03097  -3.235  0.00122
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b  0.23388    0.27480   0.851  0.39472
##                                               
## (Intercept)                                ***
## alpha_plus_mean_2a1b                          
## alpha_minus_mean_2a1b                         
## semester_study                             ** 
## UM_credits_at_study                        ** 
## alpha_plus_mean_2a1b:alpha_minus_mean_2a1b    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 468.34  on 507  degrees of freedom
## Residual deviance: 454.74  on 502  degrees of freedom
##   (329 observations deleted due to missingness)
## AIC: 466.74
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

FM ~ alpha_minus mean +/* std (base model)

interestingly the SD of alpha_minus seems to be predictive of final major across a few of these models.

Seems to be a consistent finding

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_std_2a1b + alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)            0.01031    0.07154   0.144 0.885371    
## alpha_minus_std_2a1b   0.30123    0.08129   3.706 0.000211 ***
## alpha_minus_mean_2a1b  0.09983    0.10264   0.973 0.330766    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1129.6  on 814  degrees of freedom
## Residual deviance: 1114.9  on 812  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1120.9
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "final_major_t1_STEM ~ alpha_minus_std_2a1b * alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                                             Estimate Std. Error z value
## (Intercept)                                -0.017242   0.073169  -0.236
## alpha_minus_std_2a1b                        0.372767   0.090615   4.114
## alpha_minus_mean_2a1b                       0.001126   0.114493   0.010
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b -0.214478   0.111153  -1.930
##                                            Pr(>|z|)    
## (Intercept)                                  0.8137    
## alpha_minus_std_2a1b                       3.89e-05 ***
## alpha_minus_mean_2a1b                        0.9922    
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b   0.0537 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 1129.6  on 814  degrees of freedom
## Residual deviance: 1111.2  on 811  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 1119.2
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

DTZ ~ alpha_minus mean +/* std (base model)

This is fascinating, because both are significant to predicting dropout.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_std_2a1b + alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                       Estimate Std. Error z value Pr(>|z|)    
## (Intercept)           -1.42242    0.09044 -15.727  < 2e-16 ***
## alpha_minus_std_2a1b  -0.27601    0.09397  -2.937  0.00331 ** 
## alpha_minus_mean_2a1b -0.27362    0.12412  -2.204  0.02749 *  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 810.08  on 814  degrees of freedom
## Residual deviance: 797.92  on 812  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 803.92
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

## 
## Call:
## glm(formula = "tier1_STEM_drop_tozero ~ alpha_minus_std_2a1b * alpha_minus_mean_2a1b", 
##     family = binomial, data = jrk_ABG_RR)
## 
## Coefficients:
##                                            Estimate Std. Error z value Pr(>|z|)
## (Intercept)                                -1.43341    0.09282 -15.443   <2e-16
## alpha_minus_std_2a1b                       -0.25606    0.10033  -2.552   0.0107
## alpha_minus_mean_2a1b                      -0.31886    0.14776  -2.158   0.0309
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b -0.07275    0.12729  -0.572   0.5677
##                                               
## (Intercept)                                ***
## alpha_minus_std_2a1b                       *  
## alpha_minus_mean_2a1b                      *  
## alpha_minus_std_2a1b:alpha_minus_mean_2a1b    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## (Dispersion parameter for binomial family taken to be 1)
## 
##     Null deviance: 810.08  on 814  degrees of freedom
## Residual deviance: 797.60  on 811  degrees of freedom
##   (22 observations deleted due to missingness)
## AIC: 805.6
## 
## Number of Fisher Scoring iterations: 4
## Data were 'prettified'. Consider using `terms="alpha_minus_mean_2a1b
##   [all]"` to get smooth plots.

Surivival Model

Whole Data alpha minus mean

## Call:
## coxph(formula = Surv(time = jrk_ABG$semester_drop, event = jrk_ABG$tier1_STEM_drop_tozero) ~ 
##     alpha_minus_mean_2a1b, data = jrk_ABG)
## 
##   n= 853, number of events= 165 
##    (22 observations deleted due to missingness)
## 
##                           coef exp(coef) se(coef)      z Pr(>|z|)  
## alpha_minus_mean_2a1b -0.21123   0.80959  0.08373 -2.523   0.0116 *
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                       exp(coef) exp(-coef) lower .95 upper .95
## alpha_minus_mean_2a1b    0.8096      1.235    0.6871     0.954
## 
## Concordance= 0.564  (se = 0.024 )
## Likelihood ratio test= 6.52  on 1 df,   p=0.01
## Wald test            = 6.36  on 1 df,   p=0.01
## Score (logrank) test = 5.97  on 1 df,   p=0.01

Whole Data alpha minus std

## Call:
## coxph(formula = Surv(time = jrk_ABG$semester_drop, event = jrk_ABG$tier1_STEM_drop_tozero) ~ 
##     alpha_minus_std_2a1b, data = jrk_ABG)
## 
##   n= 853, number of events= 165 
##    (22 observations deleted due to missingness)
## 
##                          coef exp(coef) se(coef)      z Pr(>|z|)  
## alpha_minus_std_2a1b -0.13830   0.87083  0.07102 -1.947   0.0515 .
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                      exp(coef) exp(-coef) lower .95 upper .95
## alpha_minus_std_2a1b    0.8708      1.148    0.7577     1.001
## 
## Concordance= 0.56  (se = 0.023 )
## Likelihood ratio test= 3.54  on 1 df,   p=0.06
## Wald test            = 3.79  on 1 df,   p=0.05
## Score (logrank) test = 3.81  on 1 df,   p=0.05

Whole Data alpha minus mean x std

## Call:
## coxph(formula = Surv(time = jrk_ABG$semester_drop, event = jrk_ABG$tier1_STEM_drop_tozero) ~ 
##     alpha_minus_mean_2a1b * alpha_minus_std_2a1b, data = jrk_ABG)
## 
##   n= 853, number of events= 165 
##    (22 observations deleted due to missingness)
## 
##                                                coef exp(coef) se(coef)      z
## alpha_minus_mean_2a1b                      -0.25326   0.77626  0.11663 -2.172
## alpha_minus_std_2a1b                       -0.17044   0.84329  0.07507 -2.270
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b -0.02554   0.97478  0.05089 -0.502
##                                            Pr(>|z|)  
## alpha_minus_mean_2a1b                        0.0299 *
## alpha_minus_std_2a1b                         0.0232 *
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b   0.6157  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                                            exp(coef) exp(-coef) lower .95
## alpha_minus_mean_2a1b                         0.7763      1.288    0.6176
## alpha_minus_std_2a1b                          0.8433      1.186    0.7279
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b    0.9748      1.026    0.8822
##                                            upper .95
## alpha_minus_mean_2a1b                         0.9756
## alpha_minus_std_2a1b                          0.9770
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b    1.0770
## 
## Concordance= 0.589  (se = 0.023 )
## Likelihood ratio test= 11.89  on 3 df,   p=0.008
## Wald test            = 13.12  on 3 df,   p=0.004
## Score (logrank) test = 13.1  on 3 df,   p=0.004

Range Restricted alpha minus mean

## Call:
## coxph(formula = Surv(time = jrk_ABG_RR$semester_drop, event = jrk_ABG_RR$tier1_STEM_drop_tozero) ~ 
##     alpha_minus_mean_2a1b, data = jrk_ABG_RR)
## 
##   n= 815, number of events= 161 
##    (22 observations deleted due to missingness)
## 
##                          coef exp(coef) se(coef)      z Pr(>|z|)  
## alpha_minus_mean_2a1b -0.2385    0.7878   0.1161 -2.055   0.0399 *
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                       exp(coef) exp(-coef) lower .95 upper .95
## alpha_minus_mean_2a1b    0.7878      1.269    0.6275    0.9891
## 
## Concordance= 0.558  (se = 0.025 )
## Likelihood ratio test= 4.25  on 1 df,   p=0.04
## Wald test            = 4.22  on 1 df,   p=0.04
## Score (logrank) test = 4.21  on 1 df,   p=0.04

Range Restricted alpha minus std

## Call:
## coxph(formula = Surv(time = jrk_ABG_RR$semester_drop, event = jrk_ABG_RR$tier1_STEM_drop_tozero) ~ 
##     alpha_minus_std_2a1b, data = jrk_ABG_RR)
## 
##   n= 815, number of events= 161 
##    (22 observations deleted due to missingness)
## 
##                          coef exp(coef) se(coef)      z Pr(>|z|)   
## alpha_minus_std_2a1b -0.21539   0.80623  0.07777 -2.769  0.00561 **
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                      exp(coef) exp(-coef) lower .95 upper .95
## alpha_minus_std_2a1b    0.8062       1.24    0.6922     0.939
## 
## Concordance= 0.572  (se = 0.024 )
## Likelihood ratio test= 7  on 1 df,   p=0.008
## Wald test            = 7.67  on 1 df,   p=0.006
## Score (logrank) test = 7.73  on 1 df,   p=0.005

Range Restricted alpha minus mean x std

## Call:
## coxph(formula = Surv(time = jrk_ABG_RR$semester_drop, event = jrk_ABG_RR$tier1_STEM_drop_tozero) ~ 
##     alpha_minus_mean_2a1b * alpha_minus_std_2a1b, data = jrk_ABG_RR)
## 
##   n= 815, number of events= 161 
##    (22 observations deleted due to missingness)
## 
##                                                coef exp(coef) se(coef)      z
## alpha_minus_mean_2a1b                      -0.29886   0.74166  0.13279 -2.251
## alpha_minus_std_2a1b                       -0.21991   0.80259  0.08747 -2.514
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b -0.07527   0.92750  0.11142 -0.675
##                                            Pr(>|z|)  
## alpha_minus_mean_2a1b                        0.0244 *
## alpha_minus_std_2a1b                         0.0119 *
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b   0.4994  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                                            exp(coef) exp(-coef) lower .95
## alpha_minus_mean_2a1b                         0.7417      1.348    0.5717
## alpha_minus_std_2a1b                          0.8026      1.246    0.6762
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b    0.9275      1.078    0.7455
##                                            upper .95
## alpha_minus_mean_2a1b                         0.9621
## alpha_minus_std_2a1b                          0.9527
## alpha_minus_mean_2a1b:alpha_minus_std_2a1b    1.1539
## 
## Concordance= 0.588  (se = 0.023 )
## Likelihood ratio test= 12.66  on 3 df,   p=0.005
## Wald test            = 12.91  on 3 df,   p=0.005
## Score (logrank) test = 13.08  on 3 df,   p=0.004