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Chapter 8: Q. 28 (page 478)

The mean age for all Foothill College students for a recent Fall term was 33.2. The population standard deviation has been pretty consistent at 15. Suppose that twenty-five Winter students were randomly selected. The mean age for the sample was 30.4. We are interested in the true mean age for Winter Foothill College students. Let X=the age of a Winter Foothill College student.

Is σxknown?

Short Answer

Expert verified

σxis unknown.

Step by step solution

01

Given Information

The mean age for all Foothill College students for a recent Fall term was 33.2. The population standard deviation has been pretty consistent at 15. The mean age for the sample was 30.4.

02

Explanation

Population standard deviation looks at the square root of the variance of the set of numbers. It's used to determine a confidence interval for concluding (such as accepting or rejecting a hypothesis).

The mean is the average of a data set. The sample mean symbol is X¯, pronounced “x bar”. The sample mean is an average value found in a sample.

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