Descriptive Sta...

Variance of the first $$11$$ natural numbers is:

If $$x $$ is multiplied by $$k$$ then $$\sigma$$  changes to

Standard Deviation of n observations $$a_1, a_2, a_3 .....a_n$$ is $$\sigma$$ Then the standard deviation of the observations $$\lambda a_1, \lambda a_2, ..., \lambda a_n$$ is

The standard deviation of $$a,a+d,a+2d,...,a+{2}{n}d$$ is

If the variance of a data is $$12.25$$, then the standard deviation is

Find the variance of the following distribution.

The mean and the variance of $$10$$ observations are given to be $$4$$ and $$2$$ respectively. If every observation is multiplied by $$2$$, the mean and the variance of the new series will be respectively.

What is the combined standard deviation of all 250 items ?

Calculate the standard deviation of the following data.

Let X denote the number of scores which exceed 4 in 1 toss of a symmetrical die. Consider the following statements :
1. The arithmetic mean of X is 6.
2. The standard deviation of X is 2.
Which of the above statements is/are correct ?