Question 4 of 7 0.5 / 1 . . . Drink Tea for a Stronger Immune System We have seen that drinking tea appears to offer a strong boost to the immune system. In a study extending the results, ' blood samples were taken on 5 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, a molecule that fights bacteria, viruses, and tumors, was measured. Mean production went from 155 pg/ml before tea drinking to 448 pg/ml after tea drinking. The mean difference for the 5 subjects is 293 pg/ml with a standard deviation in the differences of 242. The paper implies that the use of the t-distribution is appropriate. 1 Adapted from Kamath, A., et. al., "Antigens in tea-beverage prime human Vy2V82 T cells in vitro and in vivo for memory and non- memory antibacterial cytokinesresponses," Proceedings of the National Academy of Sciences, May 13, 2003; 100(10): 6009-6014. Part 1 Part 2 (b) Find a 90 % confidence interval for the mean increase in production of interferon gamma after drinking tea for one week. Round your answers to one decimal place. The 90 % confidence interval is to