In a study extending the results of the study described in the previous exercise1 , blood samples were taken on five

participants before and after one week of drinking about five cups of tea a day (the participants did not drink tea

before the study started). The before and after blood samples were exposed to E. Coli bacteria, and production of

interferon gamma was measured. Mean production went from 155 pg/mL before tea drinking to 448 pg/mL after

tea drinking. The mean difference for the five subjects is 293 pg/mL with a standard deviation in the differences

of 242. The paper implies that the use of the paired t-test is appropriate.

(e) Why is it appropriate to use paired analysis in this analysis?

(f) Please use the information herein to test whether mean production of interferon gamma as a response to

bacteria is significantly higher after drinking tea than before drinking tea. (Assume a 5% significance level).

Does your analysis fit with the conclusion stated in the paper?