Question

12. In order to estimate the mean amount of time computer users spend on the internet each​ month, how many computer users must be surveyed in order to be 90​% confident that your sample mean is within 15 minutes of the population​ mean? Assume that the standard deviation of the population of monthly time spent on the internet is 211 min. What is a major obstacle to getting a good estimate of the population​ mean? Use technology to find the estimated minimum required sample size.

The minimum sample size required is ____computer users.

​(Round up to the nearest whole​ number.)

13. Using the simple random sample of weights of women from a data​ set, we obtain these sample​ statistics: n=50 and x=145.62 lb. Research from other sources suggests that the population of weights of women has a standard deviation given by σ=32.37lb.

a. Find the best point estimate of the mean weight of all women.

b. Find a 99​% confidence interval estimate of the mean weight of all women

Answer 1