Suppose you wanted to test the effects of the herbal supplement echinacea on the length of colds. you decide to infect 10 willing participants with the rhinovirus that causes the cold, and you then give them echinacea daily. the average number of hours ill is compared with the known population mean. the z statistic based on your sample is –0.53. if you conducted a two-tailed test with a p level of 0.05, you should: