Question

For two data sets, each of size 5, the variances are given to be 4 and 5 and the corresponding means are given to be 2 and 4, respectively. The variance of the combined data set is

(a) 5/2

(b) 11/2

(c) 6 

(d) 13/2

Answer 1

(b) : Ist solution:

2nd solution :​