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Confidence Interval

  1. Nov 28, 2011 #1
    1. The problem statement, all variables and given/known data
    Janet sells cookware at home parties, she wants to estimate the average amount a client spends at each party. A random sample of 35 receipts gave a mean of X bar = $34.70 with standard deviation s = %4.85.

    a) find a 90% confidence interval for the average amount spent by all clients.

    b) for a party with 35 clients, use part (a) to estimate a range of dollar values for Janet's total sales at that party.

    2. Relevant equations

    3. The attempt at a solution

    I found the 90% confidence interval with no problem and got 33.32 < X bar < 36.09 but I don't understand what part (b) is asking, it seems to me that it is asking the same exact thing that (a) was
  2. jcsd
  3. Nov 29, 2011 #2


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    (a) is asking about the average value, while (b) is asking for a total amount from 35 clients.
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