In a simple random sample of 144 households in a county in V

In a simple random sample of 144 households in a county in Virginia, the average number of children in these households was 3.62 children. The standard deviation from this sample was 2.40 children. A 90% confidence interval for the mean number of children in all households would have a margin of error that is equal to what? Choose the closest answer from those given below.

Solution

In a simple random sample of 144 households in a county in Virginia, the average number of children in these households was 3.62 children. The standard deviation from this sample was 2.40 children. A 90% confidence interval for the mean number of children in all households would have a margin of error that is equal to what? Choose the closest answer from those given below.

Confidence Interval Estimate for the Mean

Data

Sample Standard Deviation

2.4

Sample Mean

3.62

Sample Size

144

Confidence Level

90%

Intermediate Calculations

Standard Error of the Mean

0.2

Degrees of Freedom

143

t Value

1.6556

Margin of error =t*se=

0.3311

Confidence Interval

Interval Lower Limit

3.2889

Interval Upper Limit

3.9511

Margin of error =0.3311