Question

Warren County Telephone Company claims in its annual report that “the typical customer spends $61 per month on local and long-distance service.” A sample of 12 subscribers revealed the following amounts spent last month.

$63

$66

$64

$67

$61

$64

$68

$60

$65

$59

$53

$69

a.	What is the point estimate of the population mean? (Round your answer to 3 decimal places.)

Estimated population mean

$

b.	Develop a 95% confidence interval for the population mean. (Use t Distribution Table.) (Round your answers to 3 decimal places.)

Confidence interval for the population mean

$  and $

c.	Is the company's claim that the "typical customer" spends $61 per month reasonable?
	Yes No

Answer 1

From the given sample data : Sample size = n = 12

Sample mean =

Sample standard deviation = s = 4.4747

Significance level =

a . The point estimate of the population mean =

b. The 95% confidence interval for the population mean is ,

Therefore , Confidence interval for the population mean $60.407 and $66.093

c. Here , the value %61 lies in the 95% confidence interval

Therefore , the typical customer spends $61 per month

Yes , the company;s claim is reasonable