Question

1.) Tire Kingdom installs automobile tires on a first-come-first-served basis. A random sample of 45 customers experienced an average wait time of 90.5 minutes. Assume that the standard deviation of the total wait time for all customers is 20.6 minutes. Determine the 95% confidence interval for this sample.

2.) The success of the Facebook business model depends on users clicking on ads when using the web site. A random sample of 260 Facebook users found that 169 of them click on the ads. Determine the 95% confidence interval for this sample is given by __________, __________

3.) According to market research surveys, HP controls 73% of the color inkjet printer market in the U.S. A random sample of 120 inkjet users was selected. What is the probability that 80 or more of these individuals used an HP printer?

5.) Suppose the local Best Buy store averages 475 customers per day entering the facility with a standard deviation of 120 customers. A random sample of 45 business days was selected. What is the probability that the average number of customers in the sample is less than 500?

Answer 1