Mean or Expected Value and Standard Deviation · Exercise 26

Suppose that 20,000 married adults in the United States were randomly surveyed as to the number of children they have. The results are compiled and are used as theoretical probabilities. Let X = the number of children married people have.
$$\begin{array}{ccc}\text{x}& \text{P(x)}& \text{xP(x)}\\ \text{0}& \text{0.10}& \\ \text{1}& \text{0.20}& \\ \text{2}& \text{0.30}& \\ \text{3}& & \\ \text{4}& \text{0.10}& \\ \text{5}& \text{0.05}& \\ \text{6 (or more)}& \text{0.05}& \end{array}$$

(a) Find the probability that a married adult has three children.
(b) In words, what does the expected value in this example represent?
(c) Find the expected value.
(d) Is it more likely that a married adult will have two to three children or four to six children? How do you know?

Its source prints no answer for this problem, so there's nothing to check against.

OpenStax, Introductory Statistics 2e · §4.2 Mean or Expected Value and Standard Deviation · Exercise 26