In a study of the effect of a medical treatment, a simple random sample of 300 of the 500 participating patients was assigned to the treatment group; the remaining patients formed the control group.
When the patients were assessed at the end of the study, favorable outcomes were observed in 162 patients in the treatment group and 97 patients in the control group.
Did the treatment have an effect, or is this just chance variation? Perform a statistical test, following the steps in Problems 1 through 4.
The null hypothesis is (pick the best among the options):
Under the null hypothesis, the SE of the difference between the percents of favorable outcomes in the two groups is about _______%.
The z statistic is closest
C)
The z statistic is closest to
0.8 1.0 1.2 1.4 1.6 1.8 2.0
D)
The conclusion of the test is (pick the better of the two options)
The observed difference is due to chance. The treatment has an effect.