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3. Use
function
Σ
LIST, once more, to calculate the denominator of s
w
:
4. Use the expression ANS(2)/ANS(1) to calculate the weighted
average:
Thus, the weighted average of list S with weights in list W is s
w
= 2.2.
Note:
ANS(1) refers to the most recent result (55), while ANS(2) refers to
the previous to last result (121).
Statistics of grouped data
Grouped data is typically given by a table showing the frequency (w) of data
in data classes or bins. Each class or bin is represented by a class mark (s),
typically the midpoint of the class. An example of grouped data is shown
next:
Class Frequency
Class mark count
boundaries s
k
w
k
0 - 2
1
5
2 - 4
3
12
4 - 6
5
18
6 - 8
7
1
8 -10
9
3
The class mark data can be stored in variable S, while the frequency count
can be stored in variable W, as follows:
