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Question
The marks of 20 students in a test were as follows:
2, 6, 8, 9, 10, 11, 11, 12, 13, 13, 14, 14, 15, 15, 15, 16, 16, 18, 19 and 20.
Calculate:
- the mean
- the median
- the mode
Solution
Arranging the terms in ascending order:
2, 6, 8, 9, 10, 11, 11, 12, 13, 13, 14, 14, 15, 15, 15, 16, 16, 18, 19, 20
Number of terms = 20
Σx = 2 + 6 + 8 + 9 + 10 + 11 + 11 + 12 + 13 + 13 + 14 + 14 + 15 + 15 + 15 + 16 + 16 + 18 + 19 + 20 = 257
i. Mean = `(∑x)/(∑n) = 257/20 = 12.85`
ii. Median = `(10^(th) term + 11^(th) term)/2`
= `(13 + 14)/2`
= `27/2`
= 13.5
iii. Mode = 15 as it has maximum frequencies i.e. 3
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