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Annual income: The mean annual income for people in a certain city (in thousands of dollars)...

Annual income: The mean annual income for people in a certain city (in thousands of dollars) is

40, with a standard deviation of 28. A pollster draws a sample of 90 people to interview.

(a) What is the probability that the sample mean income is less than

38? Round the answer to at least four decimal places.

(b) What is the probability that the sample mean income is between

38 and 46

(c) Find the 40th percentile of the sample mean. Round the answer to at least one decimal place.

(d) Would it be unusual for the sample mean to be less than

38? Round the answer to at least four decimal places.

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Expert Solution

orchestra answered 2 years ago
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