John Wiley & Sons TI-83 User Manual download pdf (Page 42)

Example: Finding the Area Between two values.

To find the area between two numbers a and b, type normalcdf(a, b, 0, 1).

Find the probability of getting a value between 1.04 and 1.82 on the standard normal distribution.

Press the 2

key and then the VARS key to get to the

DISTR page.

Press the number 2 key.

Type in the number 1.04, a comma, and then 1.82.

Type the mean and standard deviation 0, 1 and then ).

Press the ENTER key.

The probability is .115.

If the normalcdf( function is used to find probabilities under the standard normal distribution, it

is not necessary to type in the mean of zero and standard deviation of one. The calculator

accepts these parameters as defaults. Learning to type in these values helps to learn the proper

procedure for finding nonstandard normal probabilities.

Nonstandard Normal Probabilities

The procedure for finding probabilities of values from a nonstandard normally distributed

population are the same as those for finding probabilities from standard normal distribution.

Example:

Find the probability of getting a score of 32 given the distribution is normally distributed with a

mean of 45 and a standard deviation of 12.

Using the normalpdf( function and typing in the score

32 with a mean of 45 and standard deviation of 12

we get the probability of .018.

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John Wiley & Sons TI-83 User Manual Page 42