random Variables: continuous and discrete

1. RANDOM VARIABLES

2. VARIABLES
A variable is any characteristics, number, or quantity that can
be measured or counted. A variable may also be called a data
item. Age, sex, business income and expenses, country of
birth, capital expenditure, class grades, eye colour and vehicle
type are examples of variables. It is called a variable because
the value may vary between data units in a population,
and may change in value over time.

3. RANDOM VARIABLES
A random variable takes numerical values that
describe the outcomes of some chance process. Two
main types of random variables:
1. Discrete random variables
2. Continuous random variables

4. DISCRETE RANDOM VARIABLE
Discrete variables are countable in a finite amount of time.
For example, you can count the change in your pocket. You
can count the money in your bank account. You could also
count the amount of money in everyone’s bank accounts. It
might take you a long time to count that last item, but the point
is—it’s still countable.

5. CONTINUOUS RANDOM VARIABLE
Continuous Variables would take forever to count. In fact, you
would get to “forever” and never finish counting them.
For example, take age. You can’t count “age”. Why not?
Because it would literally take forever. For example, you could be:
25 years, 10 months, 2 days, 5 hours, 4 seconds, 4 milliseconds, 8
nanoseconds, 99 picosends…and so on.

6. To sum up …
If a variable can take on any value
between two specified values, it is called a
continuous variable; otherwise, it is called
a discrete variable.

7. AM I DISCRETE OR CONTINUOUS ??
1. If you start counting now and never, ever,
ever finish (i.e. the numbers go on and on
until infinity), you have what’s called a
variable.

8. AM I DISCRETE OR CONTINUOUS ??
If your variable is “Number of Planets around a
star,” then you can count all of the numbers out.
That is a variable.

9. The number of desks in the room
The average weight of all students
Number students in a class
Number of shoes you have
Number of books you have
Temperature in degree Celsius
Time spent in studying
Time (nearest hours) spent in studying
AM I DISCRETE OR CONTINUOUS ??

10. ACTIVITY 1
Discrete vs.Continuous
November 7, 2019
Directions: Determine if the following set of data is discrete or
continuous.
1.The heights of your classmates.
2.The number of books on your shelves.
3.The weights of watermelons.
4.The age of a person.
5.The number of words in a book.

11. ACTIVITY 1
Discrete vs.Continuous
November 7, 2019
Directions: Determine if the following set of data is discrete or
continuous.
6. number of heads when flipping three coins
7. time it takes to get to school
8. distance traveled between classes
9. students’ grade level
10. number of students present