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Warren County Telephone Company claims in its annual report that “the typical cu

ID: 3248168 • Letter: W

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.

  $64

$67

$65

$66

$59

$64

$68

$62

$64

$59

$54

$66

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

$   

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

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.

Explanation / Answer

The statistical software output for this problem is:

One sample T confidence interval:
: Mean of variable

95% confidence interval results:

Hence,

a) Point estimate = 63.167

b) 95% confidence interval: (60.599, 65.734)

c) Since this interval contains $61, the answer is Yes

Variable Sample Mean Std. Err. DF L. Limit U. Limit var7 63.166667 1.1666667 11 60.598851 65.734483