Question

Researchers designed an experiment to study the effects of caffeine withdrawal. They recruited 11 volunteers who were diagnosed as being caffeine dependent to serve as subjects. Each subject was barred from coffee, colas, and other substances with caffeine for the duration of the experiment. During one 2-day period, subjects took capsules containing their normal caffeine intake. During another 2-day period, they took placebo capsules. The order in which subjects took caffeine and the placebo was randomized. At the end of each 2-day period, a test for depression was given to all 11 subjects. The table below contains data on the subjects’ scores on the depression test with and without caffeine. Higher scores show more symptoms of depression.

Test score (caffeine)	5	5	4	3	8	5	0	0	2	11	1
Test score (placebo)	16	23	5	7	14	24	6	3	15	12	0

Construct a confidence interval for the mean difference in the test scores.

Answer 1

TOPIC:Confidence interval for the mean difference.