Author Question: Texas passed a law requiring drivers and passengers in the front seat to wear seat belts. In order ... (Read 108 times)

TVarnum · **on:** Jun 24, 2018

Texas passed a law requiring drivers and passengers in the front seat to wear seat belts. In order to estimate the compliance with the law an unmarked car will operate in a selected county and the officer will observe whether or not seat belts are in use. The proportion complying, , in the county is to be estimated by randomly selecting the cars to examine. A confidence coefficient of 0.98 is desired with the estimate, p, to be within 0.05 of the true proportion. If an average number of cars passing the observation point per day is 12,000, how many cars are needed in this sample?

Question 2

A proponent of private aid to assist those who are suffering from hunger has decided to take a random sample to estimate the average annual contribution in her community to world hunger relief. A similar study in a comparable community reported the standard deviation of giving as 15 . Our proponent believes that her estimate x should be within 3 of the true average and with 92-percent confidence. If 1222 in this community contribute to world hunger relief, what size sample is appropriate?