Professor Harde assumes that test scores are normally distributed and wants to grade "on the curve."...

Professor Harde assumes that test scores are normally distributed and wants to grade "on the curve." The mean score was 58, with a standard deviation of 14. (Round your answers to the nearest whole number.)

(a) If she wants 15% of the students to receive an A, find the minimum score to receive an A.

(b) If she wants 22% of the students to receive a B, find the minimum score to receive a B.

Solutions

Expert Solution

Ans : The mean score and standard deviation

Let X = test scores , X follows normal distribution (given)

a) If she wants 15% of the students to receive an A, then the minimum score to receive an A is

Therefore the minimum score to receive an A is 73

If she wants 22% of the students to receive a B, find the minimum score to receive a B is

Therefore the minimum score to receive a B is 69.

orchestra answered 1 year ago

Next > < Previous

Related Solutions

The time for a professor to grade an exam is normally distributed with a mean of...

The time for a professor to grade an exam is normally distributed with a mean of 12.6 minutes and a standard deviation of 2.5 minutes. 1. Compute Z-score if it took the professor 15 minutes to grade an exam 2. What is the probability that a randomly selected exam will require between 12 and 15 minutes to grade? 3. What is the probability that a randomly selected exam will require less than 15 minutes to grade?

Scores on the SAT Mathematics test are believed to be normally distributed. The scores of a...

Scores on the SAT Mathematics test are believed to be normally distributed. The scores of a simple random sample of five students who recently took the exam are 570, 620, 710, 540 and 480. We want to find a 95% confidence interval of the population mean of SAT math scores. A) Calculate the point estimate. (Round to four decimal places as needed.) B) Calculate the sample standard deviation. (Round to four decimal places as needed.) C) Calculate the standard error...

A set of test scores is normally distributed. If 80% of the scores are above 90...

A set of test scores is normally distributed. If 80% of the scores are above 90 and 30% of the test scores are below 70%, what are the mean and standard deviation of the distribution?

Suppose that scores on a test are normally distributed with a mean of 80 and a...

Suppose that scores on a test are normally distributed with a mean of 80 and a standard deviation of 8. Which of the following questions below are of type B? a. Find the 80th percentile. b. Find the cutoff for the A grade if the top 10% get an A. c. Find the percentage scoring more than 90. d. Find the score that separates the bottom 30% from the top 70%. e. Find the probability that a randomly selected student...

The scores on a math test are normally distributed with a mean of 74 and a...

The scores on a math test are normally distributed with a mean of 74 and a standard deviation of 8. The test scores range from 0 to 100. Seven students had test scores between 82 and 98. Estimate the number of students who took the test.

Suppose that scores on a test are normally distributed with a mean of 80 and a...

Suppose that scores on a test are normally distributed with a mean of 80 and a standard deviation of 8. Determine the score that would be considered the first/lower quartile (??)

the score on test for children in an eight grade class is normally distributed with a...

the score on test for children in an eight grade class is normally distributed with a mean of 70 and a standard deviation of 4.2 what is the propability a test score is less than a 77? what test score cuts off the bottom 25%? what two test score cutoff the middle 65% of the distribution?

Test scores on a university admissions test are normally distributed, with a mean of 500 and...

Test scores on a university admissions test are normally distributed, with a mean of 500 and a standard deviation of 100. d. 20% of test scores exceed what value? i know P(X>= c-500/100) = .20 but after this, i dont understand why c -500/100 =.84 where did this .84 come from?

Suppose that student scores on creativity test are normally distributed. The mean of the test is...

Suppose that student scores on creativity test are normally distributed. The mean of the test is 150 and the standard deviation is 23. Using a z-table (normal curve table), what percentage of students have z-scores a) below 1.63 b) above -0.41 Using a z-table, what scores would be the top and bottom raw score to find the c) middle 50% of students d) middle 10% of students Using a z-table, what is the minimum raw score a student can have...

) Scores on an IQ test are normally distributed. A sample of 20 IQ scores had...

) Scores on an IQ test are normally distributed. A sample of 20 IQ scores had standard deviation s = 8. The developer of the test claims that the population standard deviation is ı = 12. Do these data provide sufficient evidence to contradict this claim? Use the Į = 0.05 level of significance. 3) A) Reject H0. The population standard deviation appears to differ from 12. B) Do not reject H0. There is insufficient evidence to conclude that the...

Subjects