Question 727112: The Nielsen Company reported that children between the ages of 2 and 5 watch an average of 25 hours of television per week. Assume the variable is normally distributed and the standard deviation is 3 hours. If a group of 20 children between the ages of 2 and 5 are randomly selected, find the probability that the mean of the number of hours they watch television will be greater than 26.3 hours.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The Nielsen Company reported that children between the ages of 2 and 5 watch an average of 25 hours of television per week. Assume the variable is normally distributed and the standard deviation is 3 hours. If a group of 20 children between the ages of 2 and 5 are randomly selected, find the probability that the mean of the number of hours they watch television will be greater than 26.3 hours.
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z(26.3) = (26.3-25)/[3/sqrt(20)] = 1.9379
P(z > 26.3) = P(z> 1.9379) = 0.0263
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If you use the t-distribution you will get:
P(t > 26.3) = tcdf(1.9379,100,19) = 0.0338
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Cheers,
Stan H.
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Cheers,
Stan H.
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