Statistics Test...

The mean and standard deviation of random variable $$X$$ are $$10$$ and $$5$$ respectively, then $$E\left (\dfrac {X - 15}{5}\right )^{2} =$$ _______.

The mean of $$\displaystyle\frac{1}{3},\frac{3}{4},\frac{5}{6},\frac{1}{2}$$ and $$\displaystyle\frac{7}{12}$$ is ____________.

The mean and standard deviation of a random variable $$x$$ is given by $$5$$ and $$3$$ respectively. The standard deviation of $$2-3x$$ is _____

The arithmetic mean of the observations $$10,8,5,a,b$$ is $$6$$ and their variance is $$6.8$$, then $$ab=$$

If the standard deviation of $$0,1,2,3......,9$$ is $$K$$, then the standard deviation of $$10,11,12,13,........19$$ is

The mean age of $$25$$ students in a class is $$12$$. If the teacher's age is included, the mean age increases by $$1$$. Then teacher's age (in years) is:

If $$\sum\limits_{i = 1}^{18} {({x_i} - 8) = 9} $$ and $$\sum\limits_{i = 1}^{18} {{{({x_i} - 8)}^2} = 45} $$, then standard deviation of $${x_1},{x_2},...,{x_{18}}$$ is

Solve:

The variance of the data $$6,\ 8,\ 10,\ 12,\ 14,\ 16,\ 18,\ 20,\ 22,\ 24$$ is

Median is based on the...