Download Normal Probability Plots on the Graphing Calculator

Normal Probability Plots on the Graphing Calculator
This example uses the data on number of customers per day from a sample of 25 days at an automobile
repair station. We would like to know if the sample comes from a normal distribution.
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First, the data is entered in L1 of the calculator:
Next, go to 2nd
and choose Plot 1. Turn the Plot On, and, for Type of plot, choose the third
plot in the second row. The Data List is L1 (the list that contains your data), and the Data Axis is the X
axis. Then ZOOM 9: ZoomStat
Since there no obvious curves in the plot, we conclude that the sample came from a normal distribution.
Here Is a normal probability plot with a curve that indicates that the data did not come from a normal
distribution.