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A study of the ages of motorcyclists killed in crashes involves the random selection of 149...

A study of the ages of motorcyclists killed in crashes involves the random selection of 149 drivers with a mean of 33.24years. Assuming that sigmaσequals=8.2 ​years, construct and interpret a 90​% confidence interval estimate of the mean age of all motorcyclists killed in crashes.

Math   Statistics-And-Probability   
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Answer #1

Solution :

Given that,

Z/2 = 1.645

Margin of error = E = Z/2* ( /n)

= 1.645 * (8.2 / 149)

= 1.11

At 90% confidence interval estimate of the population mean is,

- E < < + E

33.24 - 1.11 < < 33.24 + 1.11

32.13 < < 34.35

(32.13 , 34.35)

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