1. We read that the average weight for babies born in the United States is 7.5 pounds with
deviation of 0.25 pound. We can assume that birth weights are nearly normal. If we select one
baby at random, what are the chances that the baby weighs 8 or more pounds?
a.
Normal Model is appropriate with N(7.50, 0.25, X) and P(X > 8) = 0.0228
b.
Sampling Distribution Model is appropriate with N(7.50, 0.25/root(n), Ybar)
2. We read that the average weight for babies born in the United States is 7.5 pounds with
deviation of 0.25 pound. We can assume that birth weights are nearly normal. If we select a
random sample of five babies, what are the chances that the average of the 5 weights is 8 or
more pounds?
a.
Normal Model is appropriate. N(7.50, 0.25, X) and P(X > 8) = 0.0228
b.
Sampling Distribution Model is appropriate with N(7.50, 0.25/root(5), Ybar) and P(Ybar
>8) = 0
3. A particular psychological test is used to measure academic motivation. The average test
score for all female college students nationwide is 115. A large university estimates that the
mean test score for female students on its campus by constructing a confidence interval based on
their scores. Which of the following statements about confidence intervals are true?
I. The resulting interval will contain 115.
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 Winter '08
 Ioudina
 Statistics, Normal Distribution, percent confidence interval

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