Question 176048
A consumer agency tested 290 hams, finding that 64 were underweight. 
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(a) Construct a 95 percent confidence interval for the true percent of underweight hams. 

p-hat = 64/290 = 0.22
E = 1.96*sqrt{0.22*0.78/290] = 0.477
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95% C.I.: 0.22-0.4777 < p < 0.22+0.477
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(b) If the goal is to reduce the incidence of underweight hams to 25 percent or less, does this sample show that the goal is being achieved? 
No. since there is a range of numbers in the C.I. above 0.25
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(c) Explain how this confidence interval is equivalent to a two-tailed test at &#945; = .05.
I'll leave that to you.  Compare the right tail of the C.I. to the
right tail of the Critical Value of a one-proportion ZTest.
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Cheers,
Stan H.