204 Fundamentals of Statistics
3 Click the Data Values button and select AV G from the list of range
names. Click the OK button.
4 Click the Output button and send the probability plot to a chart
sheet named Batting Average P-plot.
5 Click the OK button to start creating the normal probability plot. See
Figure 5-17.Figure 5-17
Normal
probability
plot of the
batting
average
data6 Save your changes and close the workbook.
The batting average data follow a general straight line trend on the nor-
mal probability plot pretty well. The only serious departures from the line
occur at either end of the distribution of normal scores. You can examine
the normal scores to determine what the batting averages at the end of the
distribution would be if the sample data more closely followed the nor-
mal distribution.
To convert a normal score back to the scale of the original data, you mul-
tiply the normal scores by the standard deviation of the observed values
and then add the sample average. In this case, the average batting average is
0.275528, and the standard deviation is 0.022529. If the largest normal score is