Question

The following table shows the probability distribution for a discrete random variable.

X 22 24 25 30 33 37
P(X) 0.16 0.09 0.18 0.12 0.24 0.21
What is the mean of this discrete random variable? That is, what is E(X), the expected value of X?

A. 30.27
B. 27.5
C. 29.47
D. 28.5

Answer 1

\[\large E(X)=\sum_{}^{}xp(x)\]
The first two terms are (22 * 0.16) and (24 * 0.09)

Answer 2

The expected value is the sum of six terms:
\[\large E(X)=(22\times0.16)+(24\times0.09)+...................+(37\times0.21)\]
Can you put in the missing three terms, and then add the six terms?

Answer 3

29.47?

Answer 4

then what do i do?

Answer 5

@kropot72

Answer 6

The expected value is the mean. You have finished. Obviously the correct choice is C.

Answer 7

haha sorry

Answer 8

np