## The Normal Distribution

This is where we will use our actual data not the Z-scores.) It follows a procedure very similar to Standard Normal Distribution.

Press ( you will see screen below)

Let's use these values from a homework assignment : The mean price of an entree =\$ 8.93 , with known standard deviation s = \$2.00

Say we want to find the probability that an entrŽe item chosen at random will fall between \$10.00 and \$12.00.

Once again we want to choose "2 : normalcdf ( " , and press but this time we will need to enter 4 pieces of data. They must be entered in this order :
(Lower limit , upper limit , mean , standard deviation)

Here we will use the actual data not the Z-scores!
For our problem we will use these values ( 10 , 12 , 8.93 , 2 ) You should be looking at this screen :

Now enter 10 12 8.93 2

.2339329725 will be displayed.

This is the probability that an item from the menu will fall between \$10.00 and \$12.00 .

Said another way it is the area under the curve between 10.00 and 12.00 of a Normal Distribution with mean = 8.93 and known standard deviation = 2.00.

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If you want to see a graph of this problem we will need to return to the distributions menu and Arrow right to "DRAW".

[We will follow the same procedure as before except we will enter 4 pieces of data.]

Press (You will see this screen )

Now we will enter 10 12 8.93 2

Before you press you need to adjust the WINDOW to fit your data !