Confidence Intervals. For each of the following problems include the confidence interval (don't forget units) and answer the followup question.

1. Nordstrom's CEO claims that its customers, on average, spend 15 minutes in the shoe department. You do an observational study of 50 customers in the Corte Madera Nordstrom's and find that the mean amount of time these customers spend is 12 minutes with a standard deviation of five minutes. Construct a 90% confidence interval for the mean amount of time Corte Madera Nordstrom's shoppers spend in the shoe department. Does your confidence interval support or refute the CEO's claim? Explain.

Hi can you please specify what buttons/steps you press on the Ti84 calculator if used to solve this problem please. Thank you so much for your help!!!!