Question

answer this question​

Answer 1

Answer:

Here’s ur answer....

Step-by-step explanation:

We know that,

Mean=no.of observations/total no.of observations

First group:

20=n1/15

20*15=n1

n1=300. -1st equation

Second group:

25=n2/20

25*20=n2

n2=500. -2nd equation

Adding equation 1&2,

Mean of 35 observations=n1+n2

35=300+500

35=800

Mean=800/35

Mean=22.9(approx.)

Therefore, the mean of all 35 observations is 22.9.

Hope it helps....

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