Describe each of the following values as (A) a discrete random variable, (B) a continuous random variable, or (C) not a random variable:
1. Exact weight of quarters now in circulation in the United States
2. Shoe sizes of humans
3. Political party affiliations of adults in the United States
A. 1.C
2.A
3.В
B. 1.B
2.A
3.С
C. 1.A
2.C
3.В
D. 1.A
2.В
3.С

A random variable is a variable that denotes a set of all the possible outcomes of a random experiment. It is denotes by a single capital letter such as X or Y.

There are two types of random variables.

Discrete random variable: These type of random variable takes finite number of values, such as 0, 1, 2, 3, 4, ... For example, number of girl child in a neighborhood.
Continuous random variable: These type of random variables takes infinite number of possible values. For example, the height, weight.

(1)

Exact weight of quarters now in circulation in the United States.

The variable weight is a continuous variable.

Thus, the exact weight of quarters now in circulation in the United States is a continuous random variable.

(2)

Shoe sizes of humans.

The shoe size of a person are discrete and finite values.

Thus, the shoe sizes of humans are discrete random variables.

(3)

Political party affiliations of adults in the United States.

This variable is not a quantitative variable.

It is a qualitative variable.

Thus, the political party affiliations of adults in the United States is no random variable.