Professor Sanchez has been teaching Principles of Economics

Professor Sanchez has been teaching Principles of Economics for over 25 years. He uses the following scale for grading.

Part (a) omitted

Convert the above probability distribution to a cumulative probability distribution. (Round your answers to 3 decimal places.)

What is the probability of earning at least a B in Professor Sanchez’s course? (Round your answer to 3 decimal places.)

What is the probability of passing Professor Sanchez’s course? (Round your answer to 3 decimal places.)

Grade	Numerical Score	Probability
A	4	0.090
B	3	0.240
C	2	0.390
D	1	0.160
F	0	0.120

Solution

Grade Numerical Score Probability Cumlative Probability A 4 0.09 0.09 B 3 0.24 0.33 C 2 0.39 0.72 D 1 0.16 0.88 F 0 0.12 1 b) P( Atleast B) = 1 - P(A) = 1 - 0.09 = 0.91