Question

The scores on a certain exam are normally distributed with a mean of 50 and a standard deviation of 10. a. What is the probability that a randomly selected student scored more than 65 on the exam? b. What percentage of students scored between 45 and 55?

Name: the scores on a certain exam are normally distributed with a mean of 50 and a standard deviation of 10 a what is the probability that a randomly selected student scored more than 65 on the exam b wh 2
Uploaded: 2023-08-22T01:23:44-08:00
Duration: 1 min 31 s
Channel: Tim Thornhill
Description: the scores on a certain exam are normally distributed with a mean of 50 and a standard deviation of 10 a what is the probability that a randomly selected student scored more than 65 on the exam b wh 2

          The scores on a certain exam are normally distributed with a mean of 50 and a standard deviation of 10.

a. What is the probability that a randomly selected student scored more than 65 on the exam?
b. What percentage of students scored between 45 and 55?

Added by John D.

Instant Answer

Solved by Expert Tim Thornhill

08/22/2023

Step 1

The z-score is calculated as (X - μ) / σ, where X is the score, μ is the mean, and σ is the standard deviation. So, the z-score for 65 is (65 - 50) / 10 = 1.5. Looking up 1.5 on the z-table, we find that the area to the left of this z-score is 0.9332, which means Show more…

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The scores on a certain exam are normally distributed with a mean of 50 and a standard deviation of 10. a. What is the probability that a randomly selected student scored more than 65 on the exam? b. What percentage of students scored between 45 and 55?