The sample mean was given to be x = 16.5 customer contacts and the sample standard deviation was given to be s = 4.2 customer contacts for a sample of n = 68 weekly reports. The value of ta/2 was determined to be 1.996. All the values are now known to construct the confidence interval. The lower bound of the confidence interval is calculated using the expression x-ta/2 √ Find this lower bound, rounding the result to two decimal places. 2/2 (√₁) lower bound = x-ta/25 = 16.5 1.996 = 15.45 S + a/2 √n upper bound = x+t S The upper bound of the confidence interval is calculated using the expression x + ta/2√ Find this upper bound, rounding the result to two decimal places. = 16.5 1.996 4.2 = 17.53 X √68 4.2 √68 ✓ x Therefore, the 95% confidence interval for the population mean number of weekly customer contacts for the sales personnel is from a lower bound of 15.45 17.53 X contacts/week. X contacts/week to an upper bound of