Q3 of 40 Page 210

If the mean of the following frequency distribution is 7.2 find value of ‘K’.

Given is the frequency distribution table for ungrouped data.

We have



Mean of such ungrouped data is given by



⇒


⇒ [∵ Mean = 7.2]


⇒ 7.2(40 + K) = 260 + 10K


⇒ 288 + 7.2K = 260 + 10K


⇒ 10K – 7.2K = 288 – 260


⇒ 2.8K = 28


⇒ K = 28/2.8


⇒ K = 10


Thus, K = 10.


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