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.

Four scenarios of statistical studies are given below. Decide which study uses a population parameter. Answer 1000 of the 1883 participants in last year's Ironman in Kona, Hawail were interviewed. \( 68 \% \) of those interviewed said they became interested in triathlons after first ofmpeting in marathons. 351 dog owners who were surveyed, 70 reported owning two dogs. Parkland Hospital performs 15,000 births a year. Of 1000 subjects in a study on multiple births, 38 gave birth to twins. in \( 2001.78 \% \) of children diagnosed with cancer were in remission after five years, and this number is improving.

A water bottling facility has a mean bottling rate of 35.2 thousand bottles per hour with a standard deviation of 2.04 thousand bottles, A nearby cola bottling facility has a mean bottling rate of 26.9 thousand bottles per hour with a standard deviation of 1.51 thousand bottles. One Wednesday from noon to \( 1: 00 \) p.m., the water bottling facility bottled 36.9 thousand bottles of water, and the cola bottling facility bottled 27.9 thousand bottles of cola. Which facility increased their efficiency more during that hour? Answer

Construct a box plot from the given data. Diameters of Cans in an Assembly Line: \( 5.8,5.7,5.2,5.5,5.3,5.7,5.8,5.4,5.9,5.3 \)

Suppose that IQ scores have a bell-shaped distribution with a mean of 95 and a standard deviation of 16 . Describe where the highest and lowest \( 32 \% \) of IQ scores lie. Answer botween 47 and 143 below 79 and above 111

Identify the population, the sample, and any population parameters or sample statistics in the given scenario. In the 1960 s, a poll of 2617 homeowners in the United States resulted in a report that the average price of a house in the U.S. was \( \$ 18,500 \). Answer O Population: none given: Sample: 2617 homeowners polled: Sample Statistic: \( \$ 18,500 \) Opopulation: U.S. homeowners: Sample: none given; Population Parameter: \( \$ 18,500 \)