The Expert: Simulations & Random Numbers - HP 39gs Master Manual

T E : S
T E : S
H E X P E R T
H E X P E R T
New columns as functions of old
You have already seen the use of one trick when we created a new column
the view. This can be used to create new columns as functions of any number of others. For example,
HOME
a set of data that you suspect is exponential could be 'straightened' by storing
column. Changes of scale and origin can be investigated in this way by storing (say)
You can even combine columns such as
If you don't particularly need to see the data as a fresh column, you can
use the view to accomplish the same thing in a simpler way. For
SYMB
example, the view snapshot on the right would accomplish the
SYMB
same thing as storing
2*C1
same as the one we produced earlier using the
command would give exactly the same results. The advantage
of this is that it takes much less memory if both columns need not be stored.
For the teacher this can be a handy way to create sets of data that conform to particular models. For
example, if you would like a set of data that conforms to a model of
values randomly into
C1
result will be a set of y values which exactly match the model and this is not desirable. The teacher should
now go through them and introduce some random error so that they are no longer a perfect fit.
Simulating Dice
The most common experiments in probability involve the rolling of dice. This can be simulated in the Statistics
aplet using the menu function
MATH
The syntax is:
MAKELIST( expression, variable name, start, end, increment )
where
and
For example:
MAKELIST(X2,X,1,10,2)
would produce { 1, 9, 25, 49, 81 } as
&
&
I M U L A T I O N S
I M U L A T I O N S
C1 + C2
into . A histogram of
C2
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and then, in , perform the calculation
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MAKELIST
expression
variable name
start
end
increment
R A N D O M N
R A N D O M N
.
C3
would look the
H2
view, and the
y ˆ = 2.5e
2.5*e^(0.03C1) C2
. (For more detail see page 190)
is the mathematical rule used to
generate the numbers.
is the letter (X, Y etc.) that is to be
used in the expression (any other
letters will be taken as constants).
is the first value variable name is to take.
is the upper bound for variable name.
is the amount that variable name
should be incremented by in each
iteration.
went from 1 to 3 to 5 to ...
X
120
U M B E R S
U M B E R S
by storing into
C1 2*C1
into a fresh
LN(column)
-2*C1 + 3
then simply enter any
0.03 x
. Of course, the
19
using
C2
into .
C2