2. Target Skills
1. Illustrate a random variable.
2. Classify random variables as discrete or
continuous.
3. Find the possible values of a random
variable.
3. Random Variable
Is a function that associates a real number
with each element in the sample space. It is a
variable whose values are determined by
chance.
5. Illustrative Example:
Suppose three coins are tossed. Let Y be
the random variable representing the number
of tails that occur. Find the probability of each
of the values of the random Y.
6. The Solution is shown below.
Steps Solution
1. Determine the sample space. Let H represent
head and T, tail.
The sample space for this experiment is S = {TTT,
TTH, THT, HTT, HHT, HTH, THH, HHH}
2. Count the number of tails in each outcome in
the sample space and assign this number to this
outcome.
7. Discrete Random Variable
It is a set of possible outcomes is countable.
Example:
1. Number of sales
2. Number of calls
3. Shares of stock
4. People in line
5. Mistakes per page
8. Continuous Random Variable
It is takes on values on the continuous scale.
Example:
1. Length
2. Depth
3. Volume
4. Time
5. Weight
