Little Bowen

07/01/2023 · escuela secundaria

Use the Methods for Inferences About Two Independent Means flow chart interactive to answer the following question. A random sample of 100 adult females is obtained for an experiment designed to test the efficacy of a treatment for lowering blood pressure. Fifty of them are randomly selected for the treatment group and the other 50 are assigned to the placebo group. A hypothesis test is conducted test for equality of the mean blood pressure level for the two groups before the treatment and placebo are administered. Which of the following is correct? Choose the correct answer below. A. Never assume that two independent samples are from populations with equal standard deviations. B. Because the two groups are randomly selected from the same collection of 100 subjects, the two populations have standard deviations that are both known. C. Because one group will be given a treatment while the other group is given a placebo, it cannot be assumed that the two populations have equal standard deviations. D. It makes sense to assume that the two groups have the same standard deviation so that the pooled standard error is used.