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Homework Help: Which formula do I use. Megastats Excel Statistics homework problem

  1. May 13, 2008 #1
    1. The problem statement, all variables and given/known data

    The Warren County Telephone Company claims in its annual report that “the typical customer spends $60 per month on local and long distance service.” A sample of 12 subscribers revealed the following amounts spent last month.

    $64 $66 $64 $66 $59 $62 $67 $61 $64 $58 $54 $66

    a. What is the point estimate of the population mean?

    b. Develop a 90 percent confidence interval for the population mean.

    c. Is the company’s claim that the “typical customer” spends $60 per month reasonable?
    Justify your answer using the confidence interval.

    2. Relevant equations

    Sample population? 12
    Confidence Interval 90%

    3. The attempt at a solution

    I know I can use megastats to solve this problem, I am just drawing a blank on which formula to use. WHen I click on Descriptive statistics, it comes back saying "not enough data selected". I tried Confidence Interval and I tried both:
    Sample size-mean
    sample size- p

    I must be entering something wrong somewhere.
    Can someone just tell me which formula to use? I am drawing a blank..

  2. jcsd
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