Calculate the variance of 2, 4, 7, 8 and 9
A
7.2
B
6.8
C
3.5
D
2.6
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
x
2
4
7
8
9
(\(\bar{x} - \bar{x}\))
-4
-2
1
2
4
(\(\bar{x} - \bar{x})^2\)
16
4
1
4
9
_________
\(\sum (x - x)^2\) = 34
\(\bar{x} = \frac{2 + 4 + 7 + 8 + 9}{5} = 6
variance = \(\frac{34}{5}\)
= 6.8
Source: Myschool Past Questions Archive (Record #57381)