An economics professor has determined the following probability distribution for X the grades in the final...
An economics professor has determined the following probability distribution for X the grades in the final exam in Principals of Economics course.
|
Grade |
X |
P(X) |
|
A |
4 |
0.15 |
|
B |
3 |
0.35 |
|
C |
2 |
0.25 |
|
D |
1 |
0.15 |
|
F |
0 |
0.10 |
- Compute the expected value (mean) grade that a student will earn in this course.
- Compute the variance and standard deviation of grades that students will earn in this course.
- What is the probability that a student will earn a grade of at least 2.0? P(X ≥ 2.0)
- What is the probability that a student will earn a grade of at most 1.0? P(X ≤ 1.0)
Homework Answers
a)
Mean = 
b)
Now,
So, 
Thus, 
c)
Required probability = 
d)
Required probability = 
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If using/finding zz-values, use three decimals.
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