Question 353761
Assume a very large normally distributed population of scores on a test with mean 77 and standard deviation 7. 
a. Find the two sided interval that includes 90% of this population
-1.645 < z < 1.645
x = -1.645*7+77 = 65.49
x = 1.645*7+77 = 88.51
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b. Suppose a sample of 40 members is randomly selected from this population. Find an interval (two sided) that provides a 5% error in the estimation of this sample.
? Estimation of what?
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c. What is this interval for a random sample of 300 members
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Cheers,
Stan H.