Question

Select the correct answer from each drop-down menu. The average time taken to complete a test follows normal probability distribution with a mean of 70 minutes and a standard deviation of 25 minutes. The probability of a randomly selected student completing the test in 45 minutes or less is approximately equal to %. The probability of a randomly selected student completing the test in 95 minutes is %.

Answer 1

Explanation:

Select the correct answer from each drop-down menu.

We solve using z score formula

z-score is z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation.

The average time taken to complete a test follows normal probability distribution with a mean of 70 minutes and a standard deviation of 25 minutes.

a) The probability of a randomly selected student completing the test in 45 minutes or less is approximately equal to %.

z = 45 - 70/25

b) The probability of a randomly selected student completing the test in 95 minutes is %.

z = 95 - 70/25