HP 30b Business Professional Calculator - Manual (Page 29)

Mathematical Calculations 21
Press
O
to cancel the Math menu and return to current work. Press
:s
to return
to the top of the Math menu.
For example, using the math menu calculate Sin –1 (0.5), see Table 2-5.
In the Math menu, PI does not perform calculations; it enters PI for calculations. You may start
an operation, use the Math menu to execute a function, and continue calculating with your
original operation without losing your work.
The Probability Sub-menu
Lower Tail Normal Distribution (LTND) calculates the probability for a normally distributed,
random variable to be less than the input.
Inverse Lower Tail Normal Distribution (LTND
-1
) is the inverse function for LTND; it calculates
the value (V) for which the probability of a normally distributed, random variable to be less
than V is the given input. Student, Inverse Student, Chi
2 ( 2 ), Inverse Chi 2 , F-Distribution and
Inverse F-Distribution perform similar operations for Student, Chi 2 , and F-Distributions.
Student, Chi 2 , and F-Distribution and their inverse operations are special cases, as they
require more than one number as input. Student and Chi 2 require (N), the number of degrees
of freedom, and F-Distribution requires (N1) and (N2), two degrees of freedom.
To perform Student and Chi
2 operations or their inverse:
1. Enter the number of degree(s) of freedom by typing the number and pressing
I
or
=
.
2. Type the number for which you want to calculate the probability, or, for the inverse, the
probability for which you want the number.
3. Navigate to the appropriate function in the Probability sub-menu of the Math menu.
To perform F-Distribution operations or their inverse:
Table 2-5 Math Menu Example
Keys Display Description
.5I
:s
Enters 0.5 and opens the Math menu starting
with Trigonometry.
I<
Selects the Trigonometry sub-menu and scrolls to
Sin
-1 . Note the value for Sin -1 is calculated
immediately and displayed.
I
or
=
Validates the result.
χ