Question

formula of combind mean

Answer 1

Combined arithmetic mean can be computed if we know the mean and numberof items in each groups of the data.The following equation is used to compute combined mean.Let
21
x&x
are the mean of first and second group of data containing N
1
&N
2
items respectively.Then,combined mean =
21221112
NNxNxNx

If there are 3 groups then
321332211123
NNNxNxNxNx


Answer 2

this is the answer of combined mean but the question you have to do yourself