# The Mth/prob Menu - Part 2; The Normal Distribution - HP 48gII User Manual

Graphing calculator.

start lists of random numbers is presented in detail in Chapter 17 of the user's
guide.

## The MTH/PROB menu - part 2

In this section we discuss four continuous probability distributions that are
commonly used for problems related to statistical inference: the normal
2
distribution, the Student's t distribution, the Chi-square (χ
) distribution, and the
F-distribution. The functions provided by the calculator to evaluate
probabilities for these distributions are NDIST, UTPN, UTPT, UTPC, and UTPF.
These functions are contained in the MTH/PROBABILITY menu introduced
earlier in this chapter. To see these functions activate the MTH menu:
„´ and select the PROBABILITY option:

### The Normal distribution

Functions NDIST and UTPN relate to the Normal distribution with mean µ ,
and variance σ
2
.
To calculate the value of probability density function, or pdf, of the f(x) for the
2
normal distribution, use function NDIST(µ,σ
,x). For example, check that for a
normal distribution, NDIST(1.0,0.5,2.0) = 0.20755374. This function is
useful to plot the Normal distribution pdf).
The calculator also provides function UTPN that calculates the upper-tail
2
normal distribution, i.e.,
UTPN(µ,σ
, x) = P(X>x) = 1 - P(X<x), where P()
represents a probability. For example, check that for a normal distribution,
with µ = 1.0, σ
2
= 0.5, UTPN(1.0,0.5,0.75) = 0.638163.
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