Question

The following table shows the probability distribution for a discrete random variable. X 24 26 27 32 35 39 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. 30.5 B. 31.47 C. 32.63 D. 29.5

Answer 1

expected value = \(\sum_{~}^{~}(X)*P(X)\)

where X is the value of the variable, and P(X) is the probability of the variable. the sigma sign means that you sum the products of X*P(X) for all values of X

starting with your problem, notice how X = 24 corresponds to a probability of 0.16, so you'd multiply 24*0.16

repeat with the rest of the values, then sum the products