Don't round until end plwase

A firm is experimenting whether to respond to customer complaints via phone or e-mail, and is interested to know how long each method takes from its employees. 36 customers were given phone responses, with a mean of 5 minutes and a standard deviation of 10 minutes. 45 customers were given e-mail responses, with a mean of 7 minutes and a standard deviation of 1 minutes. What is the upper bound of a 95% confidence interval in the difference between the mean response time by phone (condition 1) versus e-mail (condition 2)? Round your answer to two decimal points. Please use the following z-scores: . z-score for a 99% CI = 2.58 . z-score for a 98% CI = 2.33 . z-score for a 95% Cl = 1.96 . z-score for a 90% Cl = 1.64