Ask Questions, Get Answers

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

Find mean and variance of the data:

$\begin{array}{1 1}(A)\;29.09\\(B)\;43.4\\(C)\;4.89\\(D)\;5.125\end{array} $

Can you answer this question?

1 Answer

0 votes
  • To calculate Mean $\bar{x}= \large\frac{\sum f_i x_i}{\sum f_i}$
  • Variance $=\large\frac{\sum x_i^2}{n} - \bigg(\large\frac{\sum x_i}{n} \bigg)^2$
Step 2:
Mean $\bar{x}= \large\frac{\sum f_i x_i}{\sum f_i}$
$\qquad= \large\frac{2200}{22}$$=100$
Step 3:
Variance $=\large\frac{\sum x_i^2}{n} - \bigg(\large\frac{\sum x_i}{n} \bigg)^2$
$\qquad= \large\frac{\sum f_ix_i^2}{\sum f_i} - \bigg( \large\frac{\sum f_i x_i}{\sum f_i} \bigg)^2$
$\qquad= 10029.09-10000$
$\qquad= 29.09$
Hence A is the correct answer.
answered Jun 27, 2014 by meena.p
Ask Question
student study plans
JEE MAIN, CBSE, NEET Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App