A study found 1 in 200 women do not shave. If a random sample of 400 women is obtained, is the sampling proportion of women that do not shave approximately normal?  A) yes, sample was randomly selected  B) no, np<10 C) yes, sample size greater than 10% of the population.  D) no, nq<10

Overall about 14% of students who take the SAT's are coached, meaning they get help so they may do better on the exam. Suppose we take a random sample of 300 students and compute the proportion in the sample who are coached. A) What is the population & sample size? B) Within what interval will the sample proportion fall 95% of the time? ( show work)

A researcher asks random samples of residents of two separate counties as to whether they had purchased organically grown food in the last three months. He wants to determine whether the proportion of residents of one county who purchase organically grown food is greater than the proportion of residents of the second county who purchase organically grown food. Choose the appropriate test and name the population(s).   a) Two-proportion z-test; one population is all adults who buy organically grown food and the other population is all adults who do not buy organically grown food.   b) Two-proportion z-test; one population is all residents of the first county and the other population is residents of the second county.   c) One-proportion z-test; the population is all residents of a state.   d) One-proportion z-test; the population is all residents of the first county.

A researcher wishes to estimate the proportion of households with two cars.a) How large a sample is needed in order to be 99% confident that the sample proportion will not differ from the true proportion by more than 3%?b) Repear part a if a previous study indicates that the proportion of households with two cars is 25%.