- Learn to distinguish between the two types of random variables: continuous and discrete.
Discrete Random Variables and Continuous Random Variables
Random variables that assume a countable number of values are called discrete.
Random variables that can take any of the countless number of values are called continuous.
Here is a list of discrete random variables:
- The number of cars sold by a car dealer in one month: x=0,1,2,3,…
- The number of students who were protesting the tuition increase last semester: x=0,1,2,3,…. Notice that x could become very large.
- The number of applicants who have applied for the vacant position at a company: x=0,1,2,3,…
- The number of typographical errors in a rough draft of a book: x=0,1,2,3,…
Here is a list of continuous random variables:
- The length of time it took the truck driver to go from New York city to Miami: x>0, where x is the time.
- The depth of oil drilling to find oil: 0<x<c, where c is the maximum depth possible.
- The weight of a truck in a truck weighing station: 0<x<c, where c is the maximum weight possible.
- The amount of water loaded in a 12−ounce bottle in a bottle filling operation: 0<x<12.
- A random variable represents the numerical value of a simple event of an experiment.
- Random variables that assume a countable number of values are called discrete.
- Random variables that can take any of the countless number of values are called continuous.