Question

find the mean marks from the following data Marks Below 10 Below 20 Below 30 Below 40 Below 50 Below 60 number of students 4,10,18,28,40,70

Answer 1

The answer will be 23

Answer 2

$\begin {tabular} { |c|c|c|c|c| }</p><p>\cline { 1-5} marks obtained & classes & frequency &class mark & \sum f_{i}x_{i} \\</p><p>\cline {1-5} Below 10&0-10&4&5&20\\</p><p>\cline {1-5} Below 20&10-20&10&15&150\\</p><p>\cline {1-5} Below 30&20-30&18& 25&450 \\</p><p>\cline {1-5} Below 40& 30-40&28&35&980 \\</p><p>\cline {1-5} Below 50&40-50&40&45&1800 \\</p><p>\cline {1-5} Below 60& 50-60&70&55&3850\\</p><p>\cline {1-5} -&-&\sum f_{i} = 170&- &\sum f_{i}x_{i} = 7250 \\</p><p>\cline {1-5}</p><p>\end {tabular}$

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

$= \frac{7250}{170}\\= 42.65$

Therefore.,

$\red { Mean \: marks } \green{ = 42.65}$

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