R Markdown

d <- read.csv('overdue.txt',sep='')
head(d,n=5)
##   LATE BILL
## 1   16   79
## 2   47  264
## 3   22   97
## 4   47  289
## 5   47  288
m<-lm(LATE~BILL,d)
summary(m)
## 
## Call:
## lm(formula = LATE ~ BILL, data = d)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -45.846 -17.212  -0.793  19.007  47.774 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 51.98390    5.96405   8.716 9.84e-14 ***
## BILL        -0.01264    0.03128  -0.404    0.687    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 23.72 on 94 degrees of freedom
## Multiple R-squared:  0.001734,   Adjusted R-squared:  -0.008885 
## F-statistic: 0.1633 on 1 and 94 DF,  p-value: 0.687
plot(d$BILL,d$LATE)
abline(m)

d$commercial[48:96] <- 1
d$commercial[1:48] <- 0
head(d,n=5)
##   LATE BILL commercial
## 1   16   79          0
## 2   47  264          0
## 3   22   97          0
## 4   47  289          0
## 5   47  288          0
tail(d,n=5)
##    LATE BILL commercial
## 92   47  288          1
## 93   55  225          1
## 94   86   79          1
## 95   94   46          1
## 96   59  215          1
m<-lm(LATE~.,d)
summary(m)
## 
## Call:
## lm(formula = LATE ~ ., data = d)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -27.7637 -11.4760   0.4037  12.4812  29.0765 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept) 33.28599    3.91286   8.507 2.93e-13 ***
## BILL        -0.01264    0.01901  -0.665    0.508    
## commercial  37.39583    2.94375  12.703  < 2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 14.42 on 93 degrees of freedom
## Multiple R-squared:  0.635,  Adjusted R-squared:  0.6272 
## F-statistic: 80.91 on 2 and 93 DF,  p-value: < 2.2e-16
plot(d$BILL,d$LATE)
abline(m)
## Warning in abline(m): only using the first two of 3 regression coefficients

m2<-lm(LATE~commercial*BILL,d)
summary(m2)
## 
## Call:
## lm(formula = LATE ~ commercial * BILL, data = d)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -12.1211  -2.2163   0.0974   1.9556   8.6995 
## 
## Coefficients:
##                  Estimate Std. Error t value Pr(>|t|)    
## (Intercept)      2.209624   1.198504   1.844   0.0685 .  
## commercial      99.548561   1.694940  58.733   <2e-16 ***
## BILL             0.165683   0.006285  26.362   <2e-16 ***
## commercial:BILL -0.356644   0.008888 -40.125   <2e-16 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 3.371 on 92 degrees of freedom
## Multiple R-squared:  0.9803, Adjusted R-squared:  0.9796 
## F-statistic:  1524 on 3 and 92 DF,  p-value: < 2.2e-16
#plot(d$BILL,d$LATE)
#abline(m2)
(p<-predict(m2,d))
##        1        2        3        4        5        6        7        8 
## 15.29858 45.94993 18.28087 50.09200 49.92632 18.77792 43.63037 25.40524 
##        9       10       11       12       13       14       15       16 
## 18.28087 51.74883 15.46426 53.73703  9.83104 20.43475 26.39934 35.51190 
##       17       18       19       20       21       22       23       24 
## 17.94951 36.17463 27.06207 28.38753 53.57135 34.84917 32.03256 26.89639 
##       25       26       27       28       29       30       31       32 
## 37.16873 17.12109 12.15060 33.19234 38.65988 13.80743 47.44108 10.49377 
##       33       34       35       36       37       38       39       40 
## 29.05027 27.55912 39.48829 37.00305 27.72480 37.83146 52.08020 41.97354 
##       41       42       43       44       45       46       47       48 
## 36.17463 17.94951 52.24588 18.44655 27.06207 31.86688 14.63585 35.18054 
##       49       50       51       52       53       54       55       56 
## 73.11396 46.57031 42.56012 44.66070 55.92743 67.57608 84.57165 83.61684 
##       57       58       59       60       61       62       63       64 
## 92.21011 86.48127 71.58627 80.75242 83.61684 59.74666 82.66204 61.46531 
##       65       66       67       68       69       70       71       72 
## 73.30492 62.61108 44.08781 88.39088 54.01781 63.37493 83.23492 83.04396 
##       73       74       75       76       77       78       79       80 
## 83.23492 72.54108 73.11396 73.87781 72.35012 64.13877 49.62570 62.61108 
##       81       82       83       84       85       86       87       88 
## 63.75685 90.30050 61.65627 87.43607 75.02358 66.04839 70.82242 42.36916 
##       89       90       91       92       93       94       95       96 
## 51.34435 67.38512 44.27878 46.76128 58.79185 86.67223 92.97396 60.70146
plot(d$BILL,p)