Makers of generic drugs must show that they do not differ significantly from the "reference" drugs they imitate. One aspect in which drugs might differ is their extent of absorption in the blood. The data in the file DrugAbsorption.xls was taken from 20 healthy nonsmoking male subjects for one pair of drugs. This is a matched pairs design. Numbers 1 to 20 were assigned at random to the subjects. Subjects 1 to 10 received the generic drug first, and Subjects 11 to 20 received the reference drug first. In all cases, a washout period separated the two drugs so that the first had disappeared from the blood before the subject took the second.
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(a) Make a histogram of the differences (use class size of 500) to see that they appear to follow a reasonably Normal distribution with no outliers.
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(b) Consider the question: Do the drugs differ significantly in absorption? State the null and alternative hypotheses relative to this question.
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(c) Find the t test statistic.
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(d) What is the P-value for your t?
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(e) Do the drugs differ significantly in absorption at significance level ? = 0.05?
Data privided from Excel below.
| Subj |
Ref |
Generic |
| 15 |
4108 |
1755 |
| 3 |
2526 |
1138 |
| 9 |
2779 |
1613 |
| 13 |
3852 |
2254 |
| 12 |
1833 |
1310 |
| 8 |
2463 |
2120 |
| 18 |
2059 |
1851 |
| 20 |
1709 |
1878 |
| 17 |
1829 |
1682 |
| 2 |
2594 |
2613 |
| 4 |
2344 |
2738 |
| 16 |
1864 |
2302 |
| 6 |
1022 |
1284 |
| 10 |
2256 |
3052 |
| 5 |
938 |
1287 |
| 7 |
1339 |
1930 |
| 14 |
1262 |
1964 |
| 11 |
1438 |
2549 |
| 1 |
1735 |
3340 |
| 19 |
1020 |
3050 |