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wrote...
Posts: 233
2 weeks ago
According to the Centers for Disease Control, about 36% of U.S. adults were obese in 2013. To see if that has changed since the last study, a random sample of 250 U.S. adults will be checked.
a. Describe the sampling distribution model for the sample proportion (assuming no change in obesity rates) by naming the model and telling its mean and standard deviation. Justify your answer.
b. Sketch and clearly label the model.
c. What is the probability that in this group less than 25% of the adults will be found to be obese?
Textbook 

Stats: Modeling the World


Edition: 4th
Authors:
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wrote...
Posts: 279
2 weeks ago
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a. These adults are a random sample of all U.S. adults, and certainly less than 10% of them. We expect np = 250(0.36) = 90 successes and 160 failures so the sample size is large enough to use the sampling model N(0.36, 0.030).
b.

c. z = = -3.67
P( < 0.25) = P(z < -3.67) = 0.00012
1

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wrote...
2 weeks ago
Thanks
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