7. [-/4 Points] DETAILS BBBASICSTAT8 8.2.018.MI.S. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER What percentage of hospitals provide at least some charity care? Based on a random sample of hospital reports from eastern states, the following information is obtained (units in percentage of hospitals providing at least some charity care): 57.1 56.1 53.5 65.7 59.0 64.7 70.1 64.7 53.5 78.2 LO USE SALT Assume that the population of x values has an approximately normal distribution. (a) Use a calculator with mean and sample standard deviation keys to find the sample mean percentage x and the sample standard deviation s. (Round your answers to four decimal places.) X = S (b) Find a 90% confidence interval for the population average u of the percentage of hospitals providing at least some charity care. (Round your answers to one decimal place.) lower limit o/ upper limit 0%