# HP 50g User Manual Page 575

Graphing calculator.

to calculate for uniform-size classes (or bins), and the class mark is just the
average of the class boundaries for each class. Finally, the cumulative
frequency is obtained by adding to each value in the last column, except the
first, the frequency in the next row, and replacing the result in the last column of
the next row. Thus, for the second class, the cumulative frequency is 18+15 =
33, while for class number 3, the cumulative frequency is 33 + 16 = 49, and so
on. The cumulative frequency represents the frequency of those numbers that
are smaller than or equal to the upper boundary of any given class.
Class
Class
No.
i
XB
< XB
outlier
1
1
2
3
4
5
6
7
k = 8
>XB
outliers
k
Given the (column) vector of frequencies generated by the calculator, you can
obtain a cumulative frequency vector by using the following program in RPN
mode:
Bound.
XB
i
i+1
below
range
10
20
20
30
30
40
40
50
50
60
60
70
70
80
80
90
above
range
Class
Frequency
mark.
Xm
f
i
i
25
15
18
25
14
35
17
45
17
55
22
65
22
75
24
85
19
22
Cumulative
frequency
18
32
49
66
88
110
134
153
Page 18-8