Question

1) Below are data on how much of a new generic drug was absorbed into patients’ bloodstream and how much of the reference drug was absorbed. Each patient received both drugs separated by a wash-out period. The order of which drug was received first was randomised. Do the drugs differ significantly in the amount absorbed in the blood?

Subj	Reference	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

Answer 1

Here we have paired data. Let d = Reference - Generic

Following table shows the calculations:

Subj	Reference	Generic	d	(d-mean)^2
15	4108	1755	2353	5712100
3	2526	1138	1388	2030625
9	2779	1613	1166	1447209
13	3852	2254	1598	2673225
12	1833	1310	523	313600
8	2463	2120	343	144400
18	2059	1851	208	60025
20	1709	1878	-169	17424
17	1829	1682	147	33856
2	2594	2613	-19	324
4	2344	2738	-394	127449
16	1864	2302	-438	160801
6	1022	1284	-262	50625
10	2256	3052	-796	576081
5	938	1287	-349	97344
7	1339	1930	-591	306916
14	1262	1964	-702	442225
11	1438	2549	-1111	1153476
1	1735	3340	-1605	2458624
19	1020	3050	-2030	3972049
Total			-740	21778378

Sample size: n=20

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Conclusion: We cannot conclude that the drugs differ significantly in the amount absorbed in the blood.