value: 3.00 points Exercise 9-43 (LO9-2) Warren County Telephone Company claims

Question

value: 3.00 points Exercise 9-43 (LO9-2) Warren County Telephone Company claims in its annual report that the typical customer spends $62 per month on local and long-distance service. A sample of 12 subscribers revealed the following amounts spent last month. $65 $66 $64 $66 $58 $64 $67 $62 $64 $67 $55 $67 a. What is the point estimate of the population mean? (Round your answer to 3 decimal places.) Estimated population mean b. Develop a 98% confidence interval for the population mean. (Use LDistributionTable.) (Round your answers to 3 decimal places.) and S Confidence interval for the population mean Is the company's claim that the "typical customer spends S62 per month reasonable? O Yes O No c,

Explanation / Answer

Solution:- Given samples : 65,66,64,66,58,64,67,62,64,67,55,67
  
n = 12 , df = n-1 = 11

t = 2.718

a. Estimated population mean = 63.75

x = 765/12 = 63.75

s = 3.7689

b. 98% confidence interval for the population mean = X +/- t*s/sqrt(n)
= 63.75 +/- 2.718*3.7689/sqrt(12)
= 60.7928 , 66.7071
= 60.793 , 66.707 (rounded)

c. yes

  

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