# Question

Suppose Apple claims that the average wait time for a customer calling the Apple Care support line is 175 seconds. A random sample of 40 customers had an average wait time of 187 seconds. Assume the population standard deviation for wait time is 50 seconds.

a. Using a 95% confidence interval, does this sample support Apple’s claim?

b. Verify your results with Excel.

a. Using a 95% confidence interval, does this sample support Apple’s claim?

b. Verify your results with Excel.

## Answer to relevant Questions

The cost of ink cartridges for inkjet printers can be substantial over the life of a printer. Printer manufacturers publish the number of pages that can be printed from an ink cartridge in an effort to attract customers. HP ...Construct a 98% confidence interval to estimate the population mean when = 60 and σ = 12.2 for the following sample sizes: a. n = 20 b. n = 40 c. n = 60 The U. S. air traffic control system handled an average of 47,529 flights during 30 randomly selected days. The standard deviation for this sample is 6,210 flights per day. a. Construct a 99% confidence interval to estimate ...Determine the margin of error for a 95% confidence interval to estimate the population proportion with a sample proportion equal to 0.70 for the following sample sizes: a. n = 125 b. n = 200 c. n = 250 Determine the sample size needed to construct a 95% confidence interval to estimate the population mean for the following margins of error when σ = 80: a. 10 b. 15 c. 20Post your question

0