What price do farmers get for their watermelon crops? In thethird week of July, a random sample of 41 farming regions gave asample mean of x = $6.88 per 100 pounds of watermelon.Assume that σ is known to be $1.90 per 100 pounds.

(a) A farm brings 15 tons of watermelon to market. Find a 90%confidence interval for the population mean cash value of thiscrop. What is the margin of error? Hint: 1 ton is 2000pounds. (Round your answers to two decimal places.)

lower limit   Â	$
upper limit   Â	$
margin of error   Â	$

Over the past several months, an adult patient has been treatedfor tetany (severe muscle spasms). This condition is associatedwith an average total calcium level below 6 mg/dl. Recently, thepatient's total calcium tests gave the following readings (inmg/dl). Assume that the population of x values has anapproximately normal distribution.

9.5

8.8

10.5

9.1

9.4

9.8

10.0

9.9

11.2

12.1

(b) Find a 99.9% confidence interval for the population mean oftotal calcium in this patient's blood. (Round your answer to twodecimal places.)

lower limit   Â	  mg/dl
upper limit   Â	  mg/dl

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 ofhospitals providing at least some charity care):

57.1

56

53.1

66

59.0

64.7

70.1

64.7

53.5

78.2

(c) Find a 90% confidence interval for the population average μof the percentage of hospitals providing at least some charitycare. (Round your answers to one decimal place.)

lower limit   Â	%
upper limit   Â	%