Tips & Tricks - Univariate Data; New Columns As Functions Of Old; Simulating Dice - HP 39g Master Manual

T & T
T & T
I P S R I C K
I P S R I C K

New columns as functions of old

You have already seen the use of one trick when we created a new column
C1 by storing 2*C1 into C2 using the HOME view. This can easily be
extended to create new columns as functions of any number of others. For
example, a set of data that you suspect is exponential could be 'straightened'
by storing LN(column) into a fresh column. Changes of scale and origin can
be investigated in this way by storing (say) -2*C1 + 3 into C2. You can even
combine columns such as C1 + C2 C3.
If you don't particularly need to see the data as
a fresh column, you can use the SYMB view to
accomplish the same thing in a simpler way.
For example, the SYMB view snapshot on the
right would accomplish the same thing as
storing 2*C1 into C2. A histogram of H2 would
look the same as the one we produced earlier using the HOME view, and 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.

Simulating Dice

Many of the most common experiments in probability involve the repeated
rolling of dice. This can be simulated quite easily in the Statistics aplet using
the MATH menu function MAKELIST. (Covered in more detail on page 266)
The syntax is: MAKELIST( expression, variable name, start,end, increment )
where
and
For example: MAKELIST(X
would produce { 1, 9, 25, 49, 81 } as X went from 1 to 3 to 5 to ...
This lets you use MAKELIST and RANDOM to simulate a normal die.
- U
- U
S N I V A R I A T
S N I V A R I A
is the mathematical rule used to
expression
generate the numbers.
is the letter (X, Y etc.) that is to be
variable name
used in the expression (any other
letters will be taken as constants).
is the first value variable name is to take.
start
is the upper bound for variable name.
end
is the amount that variable name
increment
should be incremented by in each
iteration.
2
,X,1,10,2)
D
D
E A T A
T E A T A
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