1. Over the past several months, an adult patient has been treated for tetany (severe muscle spasms). This condition is associated with an average total calcium level below 6 mg/dl. Recently, the patient's total calcium tests gave the following readings (in mg/dl). Assume that the population ofxvalues has an approximately normal distribution.

9.90

9.40

10.30

8.90

9.40

9.80

10.00

9.90

11.20

12.10

(a)Use a calculator with mean and sample standard deviation keys to find the sample mean readingxand the sample standard deviations. (Round your answers to four decimal places.)

x= _____mg/dl

s= _____ mg/dl

Find a 99.9% confidence interval for the population mean of total calcium in this patient's blood. (Round your answer to two decimal places.)

lower limit ______ mg/dl

upper limit _____mg/dl

2.

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):

57.5

56.5

52.5

65.5

59.0

64.7

70.1

64.7

53.5

78.2

Assume that the population ofxvalues has an approximately normal distribution.(a)Use a calculator with mean and sample standard deviation keys to find the sample mean percentagexand the sample standard deviations. (Round your answers to four decimal places.)

x=____ %

s= _____%

(b)Find a 90% confidence interval for the population averageof the percentage of hospitals providing at least some charity care. (Round your answers to one decimal place.)

lower limit %

upper limit