The following questions have been proposed:

Is there a significant difference in the average GPA between male and female college students?

Is there a significant difference in the average number of early classes between the first two class years and other class years?

Do students who identify as “larks” have significantly better cognitive skills (cognition z-score) compared to “owls”?

Is there a significant difference in the average number of classes missed in a semester between students who had at least one early class (EarlyClass=1) and those who didn’t (EarlyClass=0)?

Is there a significant difference in the average happiness level between students with at least moderate depression and normal depression status?

Is there a significant difference in average sleep quality scores between students who reported having at least one all-nighter (AllNighter=1) and those who didn’t (AllNighter=0)?

Do students who abstain from alcohol use have significantly better stress scores than those who report heavy alcohol use?

Is there a significant difference in the average number of drinks per week between students of different genders?

Is there a significant difference in the average weekday bedtime between students with high and low stress (Stress=High vs. Stress=Normal)?

Is there a significant difference in the average hours of sleep on weekends between first two year students and other students?

Analysis

We will analyze the questions in detail

##   Gender ClassYear LarkOwl NumEarlyClass EarlyClass  GPA ClassesMissed
## 1      0         4 Neither             0          0 3.60             0
## 2      0         4 Neither             2          1 3.24             0
## 3      0         4     Owl             0          0 2.97            12
## 4      0         1    Lark             5          1 3.76             0
## 5      0         4     Owl             0          0 3.20             4
## 6      1         4 Neither             0          0 3.50             0
##   CognitionZscore PoorSleepQuality DepressionScore AnxietyScore StressScore
## 1           -0.26                4               4            3           8
## 2            1.39                6               1            0           3
## 3            0.38               18              18           18           9
## 4            1.39                9               1            4           6
## 5            1.22                9               7           25          14
## 6           -0.04                6              14            8          28
##   DepressionStatus AnxietyStatus Stress DASScore Happiness AlcoholUse Drinks
## 1           normal        normal normal       15        28   Moderate     10
## 2           normal        normal normal        4        25   Moderate      6
## 3         moderate        severe normal       45        17      Light      3
## 4           normal        normal normal       11        32      Light      2
## 5           normal        severe normal       46        15   Moderate      4
## 6         moderate      moderate   high       50        22    Abstain      0
##   WeekdayBed WeekdayRise WeekdaySleep WeekendBed WeekendRise WeekendSleep
## 1      25.75        8.70         7.70      25.75        9.50         5.88
## 2      25.70        8.20         6.80      26.00       10.00         7.25
## 3      27.44        6.55         3.00      28.00       12.59        10.09
## 4      23.50        7.17         6.77      27.00        8.00         7.25
## 5      25.90        8.67         6.09      23.75        9.50         7.00
## 6      23.80        8.95         9.05      26.00       10.75         9.00
##   AverageSleep AllNighter
## 1         7.18          0
## 2         6.93          0
## 3         5.02          0
## 4         6.90          0
## 5         6.35          0
## 6         9.04          0

Q1. Is there a significant difference in the average GPA between male and female college students?

## 
##  Welch Two Sample t-test
## 
## data:  GPA by Gender
## t = 3.9139, df = 200.9, p-value = 0.0001243
## alternative hypothesis: true difference in means between group 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  0.09982254 0.30252780
## sample estimates:
## mean in group 0 mean in group 1 
##        3.324901        3.123725

Q2. Is there a significant difference in the average number of early classes between the first two class years and other class years?

## 
##  Welch Two Sample t-test
## 
## data:  NumEarlyClass by ClassGroup
## t = 4.1813, df = 250.69, p-value = 4.009e-05
## alternative hypothesis: true difference in means between group FirstTwoYears and group OtherYears is not equal to 0
## 95 percent confidence interval:
##  0.4042016 1.1240309
## sample estimates:
## mean in group FirstTwoYears    mean in group OtherYears 
##                    2.070423                    1.306306

Q3. Do students who identify as “larks” have significantly better cognitive skills (cognition z-score) compared to “owls”?

## 
##  Welch Two Sample t-test
## 
## data:  CognitionZscore by LarkOwl
## t = 0.80571, df = 75.331, p-value = 0.4229
## alternative hypothesis: true difference in means between group Lark and group Owl is not equal to 0
## 95 percent confidence interval:
##  -0.1893561  0.4465786
## sample estimates:
## mean in group Lark  mean in group Owl 
##         0.09024390        -0.03836735

Q4. Is there a significant difference in the average number of classes missed in a semester between students who had at least one early class (EarlyClass=1) and those who didn’t (EarlyClass=0)?

## 
##  Welch Two Sample t-test
## 
## data:  ClassesMissed by EarlyClass
## t = 1.4755, df = 152.78, p-value = 0.1421
## alternative hypothesis: true difference in means between group 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  -0.2233558  1.5412830
## sample estimates:
## mean in group 0 mean in group 1 
##        2.647059        1.988095

Q5. Is there a significant difference in the average happiness level between students with at least moderate depression and normal depression status?

## 
##  Welch Two Sample t-test
## 
## data:  Happiness by DepressionStatus
## t = -5.6339, df = 55.594, p-value = 6.057e-07
## alternative hypothesis: true difference in means between group ModerateOrSevere and group Normal is not equal to 0
## 95 percent confidence interval:
##  -7.379724 -3.507836
## sample estimates:
## mean in group ModerateOrSevere           mean in group Normal 
##                       21.61364                       27.05742

Q6. Is there a significant difference in average sleep quality scores between students who reported having at least one all-nighter (AllNighter=1) and those who didn’t (AllNighter=0)?

## 
##  Welch Two Sample t-test
## 
## data:  PoorSleepQuality by AllNighter
## t = -1.7068, df = 44.708, p-value = 0.09479
## alternative hypothesis: true difference in means between group 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  -1.9456958  0.1608449
## sample estimates:
## mean in group 0 mean in group 1 
##        6.136986        7.029412

Q7. Do students who abstain from alcohol use have significantly better stress scores than those who report heavy alcohol use?

## 
##  Welch Two Sample t-test
## 
## data:  StressScore by AlcoholUse
## t = -0.62604, df = 28.733, p-value = 0.5362
## alternative hypothesis: true difference in means between group Abstain and group Heavy is not equal to 0
## 95 percent confidence interval:
##  -6.261170  3.327346
## sample estimates:
## mean in group Abstain   mean in group Heavy 
##              8.970588             10.437500

Q8. Is there a significant difference in the average number of drinks per week between students of different genders?

## 
##  Welch Two Sample t-test
## 
## data:  Drinks by Gender
## t = -6.1601, df = 142.75, p-value = 7.002e-09
## alternative hypothesis: true difference in means between group 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  -4.360009 -2.241601
## sample estimates:
## mean in group 0 mean in group 1 
##        4.238411        7.539216

Q9. Is there a significant difference in the average weekday bedtime between students with high and low stress (Stress=High vs. Stress=Normal)?

## 
##  Welch Two Sample t-test
## 
## data:  WeekdayBed by Stress
## t = -1.0746, df = 87.048, p-value = 0.2855
## alternative hypothesis: true difference in means between group high and group normal is not equal to 0
## 95 percent confidence interval:
##  -0.4856597  0.1447968
## sample estimates:
##   mean in group high mean in group normal 
##             24.71500             24.88543

Q10. Is there a significant difference in the average hours of sleep on weekends between first two year students and other students?

## 
##  Welch Two Sample t-test
## 
## data:  WeekendSleep by ClassGroup
## t = -0.047888, df = 237.36, p-value = 0.9618
## alternative hypothesis: true difference in means between group FirstTwoYears and group OtherYears is not equal to 0
## 95 percent confidence interval:
##  -0.3497614  0.3331607
## sample estimates:
## mean in group FirstTwoYears    mean in group OtherYears 
##                    8.213592                    8.221892