HP 33S - Grouped Standard Deviation

Statistics Programs
16–17
File name 33s-E-Manual-1008-Publication(1st).doc Page : 386
Printed Date : 2003/10/8 Size : 13.7 x 21.2 cm
55
¥


Stores 55 for the mean.
15.3
¥

Stores 15.3 for the standard
deviation.
t
D

value

Starts the distribution program and
prompts for X.
90
¥


Enters 90 for X and calculates Q(X).
Thus, we would expect that only about 1 percent of the students would do better
than score 90.
Keys:
(In RPN mode)
Display: Description:
t
I


Starts the inverse routine.
0.1
¥


Stores 0.1 (10 percent) in Q(X) and
calculates X.
¥


Resumes the inverse routine.
0.8
¥


Stores 0.8 (100 percent minus 20
percent) in Q(X) and calculates X.
Grouped Standard Deviation
The standard deviation of grouped data, S
xy
, is the standard deviation of data
points x
1
, x
2
, ... , x
n
, occurring at positive integer frequencies f1, f2, ... , fn.
∑
∑
∑
∑
−
−
=
1
2
2
)f(
f
)fx(
fx
S
i
i
ii
ii
xg
This program allows you to input data, correct entries, and calculate the standard
deviation and weighted mean of the grouped data.