Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
Home  >>  CBSE XI  >>  Math  >>  Statistics
0 votes

Find the mean and variance for each of the data : $6,7,10,12,12,4,8,12$

$\begin{array}{1 1}(A)\;9.25\\(B)\;3\\(C)\;2\\(D)\;7\end{array} $

Can you answer this question?

1 Answer

0 votes
  • Formula to calculate mean and variance :
  • Mean = $\large\frac{\sum x_i}{n}$
  • variance =$\large\frac{\sum x_i^2}{n} - \bigg( \large\frac{\sum x_i}{n} \bigg)^2$
Step 2:
Mean = $\large\frac{\sum x_i}{n}$
$\qquad= 9$
Step 3:
variance =$\large\frac{\sum x_i^2}{n} - \bigg( \large\frac{\sum x_i}{n} \bigg)^2$
$\qquad= \large\frac{722}{8} =\bigg(\large\frac{72}{8})^2$
$\qquad= 90.25 -81=9.25$
Hence A is the correct answer.
answered Jun 26, 2014 by meena.p
Ask Question
student study plans
JEE MAIN, CBSE, AIPMT Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App