The employees of a large international company would like to have vision care as part of their benefits package. A researcher needs to estimate the amount of money that employees and their beneficiaries spend on such treatment, on average. A sample of 1156 employees reveals the mean amount spent last year was $1,297.81, with a standard deviation of $173.25. We assume that the population standard deviation is close to the last number.

(a) Construct a 95% confidence interval for the population mean amount spent on vision care.

Find Za = 2What is the 95% confidence interval? (b) Construct a 98% confidence interval for the population mean amount spent on vision care. 2 Round the confidence interval values to 2 decimal places. What is the 98% confidence interval? (c) What is not true about the confidence intervals? 0 There is no relation between length of the confidence interval and the confidence level. 0 If the confidence level increases from 95% to 98%, then the confidence interval becomes longer. 0 There is a 95% chance that the confidence interval constructed in part (a) contains the true population mean amount spent on vision care. 0 The researcher is 98% confident that the confidence interval constructed in part (b) contains the true average amount spent on vision care