Question

suppose this is my data set ...in order to find the mean I have to find the class mark (x i) ...how to find class mark?!

Answer 1

$Class mark = \frac{upper \: limit + lower \: limit}{2}$

For the class 0-2,
classmark = (2+0)/2 = 2/2 = 1

Similarly for the class 10-12,
classmark = (12+10)/2 = 22/2 = 11

and so on..

The classmark is represented by xi

Answer 2

Class mark is average of upper limit and lower limit

So it's ( lower limit + upper limit)/2

like for class 0-2

lower limit -0
upper limit -2

Class mark = 0+2)/2 = 1

for 2-4

class mark = 2+4)/2 = 6/2 = 3

For 12-14

class mark = 12+14)/2 = 26/2 = 13

In this way class mark can be found

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