question_answer

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)  \[\frac{5}{2}\]                         

B)  \[\frac{11}{2}\]

C)  \[6\]                            

D)  \[\frac{13}{2}\]

E)  None of these