# Variance of Repair Cost for Dishwashers

1.) The following data set represents the repair cost (in dollars) for a random sample of 30 dishwashers (adapted from Consumer Reports)

41.82 90.07 100.05 118.77

52.81 90.35 101.32 119.01

57.80 91.68 103.59 120.70

68.16 91.72 104.19 140.52

73.48 93.01 105.62 141.84

78.88 95.21 111.32 147.06

88.13 95.34 117.14

88.79 96.50 118.42

Assume the population of dishwasher repair costs is normally distributed.

a. Construct a 95% confidence interval for the population variance.

b. Construct a 95% confidence interval for the population standard deviation.

https://brainmass.com/statistics/confidence-interval/variance-repair-cost-dishwashers-253784

#### Solution Preview

1.) The following data set represents the repair cost (in dollars) for a random sample of 30 dishwashers (adapted from Consumer Reports)

41.82 90.07 100.05 118.77

52.81 90.35 101.32 119.01

57.80 91.68 103.59 120.70

68.16 91.72 104.19 140.52

73.48 93.01 105.62 141.84

78.88 95.21 111.32 147.06

88.13 95.34 117.14

88.79 96.50 118.42

Assume ...

#### Solution Summary

The solution examines the variance of repair cost for dishwashers. A 95% confidence interval for the population distribution is given.