Explore BrainMass

# Solving for Point Estimates and Confidence Intervals

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

Question: The Warren County Telephone Company claims in its annual report that "the typical customer spends \$70 per month on local and long-distance service." A sample of 12 subscribers revealed the following amounts spent last month.

Amounts Spent Last Month:
\$64
\$57
\$59
\$68
\$60
\$65
\$69
\$56
\$58
\$56
\$55
\$56

(a) What is the point estimate of the population mean? (Round your answer to 3 decimal places)
(b) Determine the 99% confidence interval for the population mean. (Round your answer to 2 decimal places)
Note: Confidence interval is between \$ and \$.
(c) Is the company's claim that the "typical customer" spends \$70 per month reasonable?

https://brainmass.com/statistics/confidence-interval/solving-point-estimates-confidence-intervals-514952

#### Solution Preview

Hi there, here is my explanation:

a) mean=(64+57+59+68+60+65+69+56+58+56+55+56)/12=60.250

b) Since n=12<30, we need to use a t ...

#### Solution Summary

The solution gives a few lines' calculations for each part with some worded explanation.

\$2.19