Question 472827: A credit card company decides to study the frequency with which its cardholders charge for items from a certain chain of retail stores. The data values collected in the study appear to be normally distributed with a mean of 25 charged purchases and a standard deviation of 2 charged purchases. Out of the total number of cardholders, about how many would you expect are charging 17 or more purchases in this study? A. 94.8% B. 68.3% C. 47.8% D. 15.9%
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A credit card company decides to study the frequency with which its cardholders charge for items from a certain chain of retail stores. The data values collected in the study appear to be normally distributed with a
mean of 25 charged purchases and a
standard deviation of 2 charged purchases.
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Out of the total number of cardholders, about how many would you expect are charging 27 or more purchases in this study?
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z(27) = (27-25)/2 = 1
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So, the z-score of 27 is 1
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I used a TI-84 caculator to get the following:
P(x >= 27) = P(z >= 1) = normalcdf(1,100) = 15.87%
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Stan H.
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A. 94.8% B. 68.3% C. 47.8% D. 15.9%
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