Page 18-8
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
No.
Class Bound.
Class
mark.
Frequency Cumulative
i XB
i
XB
i+1
Xm
i
f
i
frequency
< XB
1
outlier below
range
25
1 10 20 15 18
18
2 20 30 25 14
32
3 30 40 35 17
49
4 40 50 45 17
66
5 50 60 55 22
88
6 60 70 65 22
110
7 70 80 75 24
134
k = 8
80
90
85
19
153
>XB
k
outliers above
range
22
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:
«
DUP SIZE 1 GET
freq k
«
{k 1} 0 CON
cfreq
«
‘freq(1,1)’ EVAL
‘cfreq(1,1)’ STO 2 k FOR j ‘cfreq(j-1,1) +freq(j,1)’ EVAL ‘cfreq (j,1)’ STO
NEXT cfreq
»
»
»
Save it under the name CFREQ. Use this program to generate the list of
cumulative frequencies (press
@CFREQ
with the column vector of frequencies in
the stack). The result, for this example, is a column vector representing the last
column of the table above.
