HP 33s - Manual (Page 277)

Statistics Programs 16–17
55 g
@
)
 Stores 55 for the mean.
15.3 g
)
 Stores 15.3 for the standard
deviation.
X D %@
value Starts the distribution program and
prompts for X.
90 g
/
)
 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:
X I @
)
 Starts the inverse routine.
0.1 g
%/
)
 Stores 0.1 (10 percent) in Q(X) and
calculates X.
g
@
)
 Resumes the inverse routine.
0.8 g
%/
) 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 f
1
, f
2
, ... , f
n
.
¦
¦
¦
¦
−
−
=
1
2
2
) f (
f
) f x (
f x
S
i
i
i i
i i
xg
This program allows you to input data, correct entries, and calculate the standard
deviation and weighted mean of the grouped data.