A doctor wants to estimate the mean HDL cholesterol of all 20-to 29-year-old females. How many subjects are needed to estimate the mean HDL cholesterol within 3 points with \( 99 \% \) confidence assuming s = 12.9 based on earlier studies? Suppose the doctor would be content with \( 90 \% \) confidence. How does the decrease in confidence affect the sample size required? Click the icon to view a partial table of critical values. A. Decreasing the confidence level decresases the sample size needed. B. Decreasing the confidence level increases the sample size needed. C. The sample size is the same for all levels of confidence.

The grades on the second statistics test for Mr. Brown's class are in the following list. Find the frequency distribution for the grades. \[ F, C, B, D, D, A, F, B, B, D, F, D, D, B, B, D, B, A, D, F, D \]

Suppose that shoe sizes of American women have a bell-shaped distribution with a mean of 8.06 and a standard deviation of 1.52 . Using the empirical rule, what percentage of American women have shoe sizes that are greater than 9.58 ? Please do not round your answer.

A water bottling facility has a mean bottling rate of 34.1 thousand bottles per hour with a standard deviation of 2.13 thousand bottles. A nearby cola bottling facility has a mean bottling rate of 25.7 thousand bottles per hour with a standard deviation of 1.63 thousand bottles. One Wednesday from noon to \( 1: 00 \) p.m., the water bottling facility bottled 37.2 thousand bottles of water, and the cola bottling facility bottled 27.7 thousand bottles of cola. Which facility increased their efficiency more during that hour? Answer

The grades on the second statistics test for Ms. Rose's class are in the following list. Find the frequency distribution for the grades. \[ \text { F, D, F, B, F, A, C, F, C, F, D, B, B, B, C, C, F, C, F, D, A } \]

Supstion 5 of 19, Step 1 of 1 percentage of American women have shoe sizes that are greater than 9.58 ? Please do not round your answer. Answer How to enter your answer (opens in new window)