Question
4 students have the following grades (out of 100): 56, 78, 92, 43. We pick two...
4 students have the following grades (out of 100): 56, 78, 92, 43. We pick two random students from these 4.
A = Average grade of the two students
What is the expected value and the variance of A?
Homework Answers
Answer #1
A can take values 56,78,92,43,67,74,49.5,85,60.5,67.5
Probability distribution of A:
| A | P(A) |
| 56 |  |
| 78 |  |
| 92 |  |
| 43 | |
| 67 |  |
| 74 |  |
| 49.5 | |
| 85 | |
| 60.5 | |
| 67.5 | |
and, 
So, 
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