Statistics And Probability Question 405

Question: One set containing five members has mean 8, variance 18 and the second set containing three members has mean 8 and variance 24. The variance of combined set of numbers is

Options:

A) 24

B) 20.25

C) 22.25

D) None of these

Show Answer

Answer:

Correct Answer: B

Solution:

[b] $ {{\sigma }^{2}}=\frac{5.18+3.24}{5+3}+(8-8)\frac{15}{64}=20.25. $