HP 33S - Page 4

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HP 33S Normal distribution applications
In RPN mode: tS
Figure 6
Since we are dealing with a standardized normal distribution, the mean should stay equal to 0.
In RPN mode: ¥
Figure 7
Since we are dealing with a standardized normal distribution, the standard deviation is equal to 1.
In RPN mode: ¥
Now, calculate Q(x) for an x value of –1 by pressing:
In RPN mode: tD
Figure 8
In RPN mode: 1z¥
Figure 9
Answer: The upper tail probability for the standardized normal distribution with a value of x equal to -1 is 0.8413.
This means that 84.13% of all values would be larger than a Z-score of –1. Conversely, 15.87% of all
values would be smaller than a Z-score of –1.
Example 3: The average number of claims processed per hour by an insurance adjuster is 15 with a standard deviation
of 4 and follows the normal distribution. If an adjuster processes 20 claims per hour, what percentage of
adjusters is this person performing faster than?
Solution: This is a normal distribution problem where the input is not standardized. Press ¹ä to enter RPN
mode. Then execute label S and enter the mean and standard deviation.
In RPN mode: tS15¥4¥
hp calculators - 4 - HP 33S Normal distribution applications - Version 1.0