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1. A college professor teaches Chemistry 101 each fall to a large class of first-year students. For tests, she uses standardized exams that she knows from past experience produce normal distributions of scores, with a mean of 70 and a standard deviation of 12. a. Her philosophy of grading is to impose standards that will yield, in the long run, 14% A's, 20% B's, 32% C's, 20% D's and 14% F's. Where should the cutoff be between the A's and the B's? Between the B's and the C's? b. According to reference tables, will a standard normal distribution have any points above 2.5? How does that translate to the distribution of scores? c. What share of points in a standard normal distribution are below -4? What does that imply for the distribution of scores?

1. A college professor teaches Chemistry 101 each fall to a large class of first-year students. For tests, she uses standardized exams that she knows from past experience produce normal distributions of scores, with a mean of 70 and a standard deviation of 12. a. Her philosophy of grading is to impose standards that will yield, in the long run, 14% A's, 20% B's, 32% C's, 20% D's and 14% F's. Where should the cutoff be between the A's and the B's? Between the B's and the C's? b. According to reference tables, will a standard normal distribution have any points above 2.5? How does that translate to the distribution of scores? c. What share of points in a standard normal distribution are below -4? What does that imply for the distribution of scores?

MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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1. A college professor teaches Chemistry 101 each fall to a large class of first-year students. For tests, she uses standardized exams that she knows from past experience produce normal distributions of scores, with a mean of 70 and a standard deviation of 12. a. Her philosophy of grading is to impose standards that will yield, in the long run, 14% A's, 20% B's, 32% C's, 20% D's and 14% F's. Where should the cutoff be between the A's and the B's? Between the B's and the C's? b. According to reference tables, will a standard normal distribution have any points above 2.5? How does that translate to the distribution of scores? c. What share of points in a standard normal distribution are below-4? What does that imply for the distribution of scores?
Transcribed Image Text:1. A college professor teaches Chemistry 101 each fall to a large class of first-year students. For tests, she uses standardized exams that she knows from past experience produce normal distributions of scores, with a mean of 70 and a standard deviation of 12. a. Her philosophy of grading is to impose standards that will yield, in the long run, 14% A's, 20% B's, 32% C's, 20% D's and 14% F's. Where should the cutoff be between the A's and the B's? Between the B's and the C's? b. According to reference tables, will a standard normal distribution have any points above 2.5? How does that translate to the distribution of scores? c. What share of points in a standard normal distribution are below-4? What does that imply for the distribution of scores?
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