Question

A researcher believes that alcohol intoxication at even half of the legal limit, that is, .05 blood alcohol instead of .10, might severely impair driving ability. To test this, he subjects 10 volunteers to a driving simulation test first while sober and then after drinking sufficient alcohol to raise the blood alcohol level to .05. The researcher measures performance as the number of simulated obstacles with which the driver collides. Thus, the higher the number, the poorer the driving. The obtained results are as follows:

Before Drinking	After Drinking
1	4
2	2
0	1
0	2
2	5
1	3
4	3
0	2
1	4
2	3

Test the null hypothesis that there is no difference in driving ability before and after alcohol consumption to the .05 blood alcohol level (use the .05 significance level). Provide the t-ratio, degrees of freedom, and the decision about the null in your answer.

Answer 1