Statistics And Probability Question 218
Question: If the algebraic sum of deviations of 20 observations from 30 is 20, then the mean of observations is
Options:
A) 30
B) 30.1
C) 29
D) 31
Show Answer
Answer:
Correct Answer: D
Solution:
$ \sum\limits_{i=1}^{20}{(x_{i}-30)=20} $
Þ $ \sum\limits_{i=1}^{20}{x_{i}-20\times 30=20} $
Þ $ \sum\limits_{i=1}^{20}{x_{i}=620} $ . Mean = $ \frac{\sum\limits_{i=1}^{20}{x_{i}}}{20}=\frac{620}{20}=31 $ .
BETA
