Use the following information to answer the question. A sprint duathlon consists of a 5 km run, a 20 km bike ride, followed by another 5 km run. The mean finish time of all participants in a recent large duathlon was 1.67 hours with a standard deviation of 0.25 hours. Suppose a random sample of 30 participants in the 40- 44 age group was taken and the mean finishing time was found to be 1.62 hours with a standard deviation of 0.40 hours.
-What is the standard error for the mean finish time of 30 randomly selected participants in the 40- 44 age group? Round to the nearest thousandth.
A)0.250
B)0.046
C)0.055
D)0.300

Question

Quizplus · Accepted Answer

The standard error of the mean is the standard deviation of the sample mean. It is calculated by dividing the standard deviation of the population by the square root of the sample size. In this case, the standard deviation of the population is 0.25 hours and the sample size is 30. Therefore, the standard error of the mean is 0.25 / sqrt(30) = 0.046 hours.

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