Question

The mean and variance of $5$ observations are $5$ and $8$ respectively If $3$ observations are $1,3,5$, then the sum of cubes of the remaining two observations is

• A. 1216
• B. 1456
• C. 1072
• D. 1792

Answer 1

Answer: (C)

1072

Answer 2

51+3+5+a+b​=5
a+b=16……(1)
σ2=5∑x12​​−(5∑x​)2
8=512+32+52+a2+b2​−25
a2+b2=130……(2)
by (1),(2)
a=7,b=9
or a=9,b=7