The times of the runners in a marathon are normally distributed, with a mean of 3 hours and 50 minutes and a standard deviation of 30 minutes. What is the probability that a randomly selected runner has a time less than or equal to 3 hours and 20 minutes? Use the portion of the standard normal table below to help answer the question.
16%
32%
34%
84%

The times of the runners in a marathon are normally distributed with a mean of 3 hours and 50 minutes and a standard deviation of 30 minutes What is the probabi class=

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Answer:

The answer is 16%

Step-by-step explanation:

Given a mean of 3 hours and 50 minutes and a standard deviation of 30 minutes

so a time less than or equal to 3 hours and 20 minutes is a time 1 standard deviation OUTSIDE from the mean

Use the probability table:

The probability that a randomly selected runner has a time less than or equal to 3 hours and 20 minutes

= Probability of z being outside 1 SD from mean

= 1 - Probability of z within 1 SD from mean

= 1 - 0.84

= 0.16 or 16%....

Answer:

A 16%

Step-by-step explanation:

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