Question

Find the mean of the data given in the following table.

Class 0-20 20-40 40-60 60-80 80-100

Frequency 6 4 5 7 3

Answer 1

$\begin {tabular} {|c|c|c|c|}</p><p>\cline {1-4} class & frequency & class mark&f_{i}x_{i} \\</p><p>\cline {1-4} 0-20&6& 10&60 \\</p><p>\cline {1-4} 20-40&4&30&120 \\</p><p>\cline {1-4} 40-60&5&50&250 \\</p><p>\cline {1-4} 60-80&7&70&490 \\</p><p>\cline {1-4} 80-100&3&90&270 \\</p><p>\cline {1-4} -&\sum f_{i} = 25 &-&\sum f_{i}x_{i} = 1190 \\</p><p>\cline {1-4} </p><p>\end {tabular}$

$Mean = \frac{\sum f_{i}x_{i}}{\sum f_{i}}$

$= \frac{1190}{25} \\= 47.6$

Therefore.,

$\red{Mean } \green {= 47.6}$

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