Assignment Direction 1

##   SubjectID Before
## 1         2   2.96
## 2        13   3.16
## 3         4   3.94
## 4        16   4.05
## 5        17   4.42
## 6        20   4.69
##   SubjectID After
## 1        12  7.23
## 2         1  6.85
## 3        14  6.42
## 4        11  6.25
## 5         7  6.09
## 6        19  6.03

Assignment Direction 2

##    SubjectID Before After
## 1          2   2.96  4.78
## 2         13   3.16  4.55
## 3          4   3.94  4.01
## 4         16   4.05  5.59
## 5         17   4.42  3.96
## 6         20   4.69  3.72
## 7          6   4.81  5.34
## 8          5   4.85  5.91
## 9         10   4.88  5.75
## 10         3   4.95  5.57
## 11        18   4.99  5.93
## 12        19   5.01  6.03
## 13         9   5.15  4.19
## 14        12   5.26  7.23
## 15         8   5.33  5.84
## 16        15   5.49  5.25
## 17        11   5.75  6.25
## 18         1   6.25  6.85
## 19         7   6.60  6.09
## 20        14   6.65  6.42

Assignment Direction 3

##    SubjectID Before After AfterMinusBefore
## 1          2   2.96  4.78             1.82
## 2         13   3.16  4.55             1.39
## 3          4   3.94  4.01             0.07
## 4         16   4.05  5.59             1.54
## 5         17   4.42  3.96            -0.46
## 6         20   4.69  3.72            -0.97
## 7          6   4.81  5.34             0.53
## 8          5   4.85  5.91             1.06
## 9         10   4.88  5.75             0.87
## 10         3   4.95  5.57             0.62
## 11        18   4.99  5.93             0.94
## 12        19   5.01  6.03             1.02
## 13         9   5.15  4.19            -0.96
## 14        12   5.26  7.23             1.97
## 15         8   5.33  5.84             0.51
## 16        15   5.49  5.25            -0.24
## 17        11   5.75  6.25             0.50
## 18         1   6.25  6.85             0.60
## 19         7   6.60  6.09            -0.51
## 20        14   6.65  6.42            -0.23

Histogram

QQ-Plot Both the histogram and QQ plot show normality. With the histogram, we can tell it is approximately normal because of it’s bell shaped curve. With the QQ plot, we can tell it is approximately normal because the points fall within the line or within the envelope.

Assignment Direction 4

Null Hypothesis:

\[H_0:\mu=0\] Alternative Hypothesis:

\[H_a:\mu>0\]

Assignment Direction 5

## 
##  Welch Two Sample t-test
## 
## data:  subtraction$After and subtraction$Before
## t = 1.6302, df = 37.994, p-value = 0.05566
## alternative hypothesis: true difference in means is greater than 0
## 95 percent confidence interval:
##  -0.01723034         Inf
## sample estimates:
## mean of x mean of y 
##    5.4630    4.9595

Decision: p-value is greater than 0.05. We do not reject the null hypothesis

Conclusion: At the level 0.05 level of significance, there is not evidence to conclude that there is an increase in the average reaction time after alcohol intake.

Work Cited:

“Paired Samples.” University of Florida Biostatistics Open Learning Textbook. https://bolt.mph.ufl.edu/6050-6052/unit-4b/module-13/paired-t-test/.