Researchers conducted a study to determine whether magnets are effective in treating back pain. The results Treatment Sham are shown in the table for the treatment (with magnets) group and the sham (or placebo) group. The results are a measure of reduction in back pain. Assume that the two samples are independent simple random CIX samples selected from normally distributed populations, and do not assume that the population standard 0.51 0.41 deviations are equal. Complete parts (a) and (b) below. 0.69 1.36 Since the for those treated with magnets is the sample mean for those given a sham treatment. it valid to argue that magnets might appear to be effective if the sample sizes are larger