The stat soft menu, The stat soft menu ,18-15 – HP 50g Graphing Calculator User Manual

Page 582

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Page 18-15

B. If n

⋅p is an integer, say k, calculate the mean of the k-th and (k-1) th

ordered observations.

This algorithm can be implemented in the following program typed in RPN
mode (See Chapter 21 for programming information):

« SORT DUP SIZE p X n « n p * k « IF k CEIL k FLOOR - NOT THEN X k
GET X k 1 + GET + 2 / ELSE k 0 RND X SWAP GET END » » »

which we’ll store in variable %TILE (percent-tile). This program requires as
input a value p within 0 and 1, representing the 100p percentile, and a list of
values. The program returns the 100p percentile of the list.

Example 1 - Determine the 27% percentile of the list { 2 1 0 1 3 5 1 2 3 6 7 9}.
In RPN mode, enter 0.27

` { 2 1 0 1 3 5 1 2 3 6 7 9} ` @%TILE. In ALG

mode, enter %TILE(0.27,{2,1,0,1,3,5,1,2,3,6,7,9}. The result is 1.

The STAT soft menu

All the pre-programmed statistical functions described above are accessible
through a STAT soft menu. The STAT soft menu can be accessed by using, in
RPN mode, the command: 96 MENU

You can create your own program, say

@STATm, to activate the STAT soft menu

directly. The contents of this program are simply: « 96 MENU ».

The STAT soft menu contains the following functions:

Pressing the key corresponding to any of these menus provides access to
different functions as described below.

Note: Integer rounding rule, for a non-integer x.yz…, if y

≥ 5, round up to

x+1; if y < 5, round up to x.

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