# TI-83 Discrete Random Variables

advertisement ### TI-83 Discrete Random Variables

Suppose that x (

L

1

) is the number of pets owned by a family and P(x) (

L

2

) is the corresponding probability.

This represents a discrete probability distribution. Enter it as seen on the right.

Mean of a Discrete Probability Distribution

The mean is calculated by

x

P

  

. Therefore, highlight

L

3

and enter

L

1

*

L

2

as seen to the right.

Pressing

ENTER

will perform the calculation as can be seen here.

Now to calculate the mean we must sum the values in

L

3

. Press

2 nd

QUIT

to go back to the home screen.

Now press

2 nd

LIST

and you should see the following display.

Key over to

MATH

and down to

5: sum(

as seen here and press

ENTER

.

Enclose

L

3

in parentheses and press

ENTER

. This gives you the mean of the Discrete Probability

Distribution.

Standard Deviation of a Discrete Probability Distribution

Use

x

2

P

2

to calculate the standard deviation. Begin by creating

L

4 to the right.

with

L

1

2

*

L

2

as seen

After pressing

ENTER

L

4

will appear as follows.

Go back to the home screen and enter the command seen in the window to the right. Press

ENTER

and you will get the standard deviation.