Why is the number of cars sold in one day a discrete random variable?
Swiss commemorative stamp of mathematician Jakob Bernoulli, issued 1994, displaying the formula and the graph for the law of large numbers, first proved by Bernoulli in 1713.
The number of cars sold in one day is considered a discrete random variable because it can only assume a finite number of values or an infinite sequence of values.12
In statistics, a random variable is classified as discrete when its possible outcomes are countable, such as 0, 1, 2, or 3 cars sold. Unlike a continuous random variable—which can take on any value within an interval on the real number line, such as a person's weight—the number of cars sold must be a whole number. Because these outcomes are distinct and finite, the probabilities associated with them are described by a probability mass function, where the sum of all possible outcome probabilities must equal one.12