1. A simple random sample from a population with a normal distribution of 100body temperatures has x bar=98.50Fand s=0.64F.Construct an80%confidence interval estimate of the standard deviation of body temperature of all healthy humans. Is it safe to conclude that the population standard deviation is less than 2.10F?

F F

2.

The body mass index(BMI) for a sample of men and a sample of women are given below. Assume the samples are simple random samples obtained from populations with normal distributions.

Men	23.6	32.5	21.2	25.5	25.6	32.3	32.4	30.3	26.1	21.5
Women	18.8	20.7	24.9	30.7	18.5	23.6	18.5	30.7	17.4	24.3

A.Construct a95%confidence interval estimate of the standard deviation of BMIs for men. ? men

B.Construct a95% confidence interval estimate of the standard deviation of BMIs for women. ? women

3.Listed below are speeds(mi/h) measured from traffic on a busy highway. This simple random sample was obtained at3:30 P.M. on a weekday. Use the sample data to construct aa90%confidence interval estimate of the population standard deviation.

63

64

64

56

64

53

59

58

59

69

60

68

The confidence interval estimate is ?mi/h