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

ID: 2949834 • 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

$65

$63

$69

$57

$65

$68

$63

$64

$61

$54

$69

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

Develop a 98% confidence interval for the population mean. (Use t Distribution Table.) (Round your answers to 3 decimal places.)

  $64

$65

$63

$69

$57

$65

$68

$63

$64

$61

$54

$69

Explanation / Answer

The statistical software output for this problem is:

One sample T confidence interval:
? : Mean of variable

98% confidence interval results:

Hence,

a) Point estimate = 63.5

b) 98% confidence interval: (59.951, 67.049)

c) Yes

Variable Sample Mean Std. Err. DF L. Limit U. Limit Data 63.5 1.3055824 11 59.951324 67.048676