Question

The mean of five observations is $4.4$ and the variance is $8.24$.Three of the five observations are $1,2$ and $6$. The remaining two are

• A. $9,4$
• B. $7,6$
• C. $6,5$
• D. $10,3$

Answer 1

The correct option is A $9,4$

Let the other nos. be a and b
then
$\frac{a+b+1+2+6}{5}=4.4$
$a+b=13$ ---------------------(1)

Variance = 8.24
$(1-4.4{)}^2+(2-4.4{)}^2+(6-4.4{)}^2+(a-4.4{)}^2+(b-4.4{)}^2=8.24\ast 5$-------- (2)
Solve (1) and (2)
a = 9, b=4