Let x be a random variable that represents the number of students who are absent on a given day from a class of 25. The following table lists the probability distribution of x.
| X |
P(X) |
| 0 |
0.08 |
| 1 |
0.18 |
| 2 |
0.32 |
| 3 |
0.22 |
| 4 |
0.14 |
| 5 |
0.06 |
a) Determine the following probabilities:
p(x = 4), p( x > 4), p ( 2 < x < than 4), and p( x greater than 1).
b)Determine the expected number of absent students on a given day.
c) Compute the variance of x by the definition.
d) Compute the variance of x by the short cut formula.
e) Determine the standard deviation of x