A random sample of ten households having landline telephone services in your community was conducted. The monthly expenses for landline telephone service at the selected ten households were as follows: $/month 47, 39, 42, 51, 36, 51, 42, 39, 41, 55

Determine a 95% confidence interval for the average monthly expenditure for landline telephone service.

Sample Mean:

Sample Median:

Sample Standard Deviation

Degree of Freedom

Sample Standard Error:

T-distribution critical value:

(From t-Distribution Critical Values Table)

Confidence Interval:

A random sample of 15 customers behavior towards usage of mobile telephones through a survey of how much is their monthly expenses for service. The survey revealed the following: $/month 35, 55, 45, 60, 65, 40, 75, 70, 80, 90, 85, 100, 50, 105, 95.

Determine a 95% confidence interval for the average monthly expenditure for landline telephone service.

Sample Mean:

Sample Median:

Sample Standard Deviation

Degree of Freedom

Sample Standard Error:

t-distribution critical value:

(From t-Distribution Critical Values Table)

Confidence Interval: