Statistics Test...

The Mean deviation about A.M. of the numbers $$3, 4, 5, 6, 7 $$ is :

The range of the data 25.7, 16.3, 2.8, 21.7, 24.3, 22.7, 24.9 is

If the mean of the observations:
$$x, x + 3, x + 5, x + 7, x + 10$$ is $$9$$, the mean of the last three observations is

If the standard deviation of $$5, 7, 9$$ and $$11$$ is $$2$$, then the coefficient of variation is?

The range of the data 7,9,7,5,9,9,18,6,8,9 is:

The mean marks (out of $$100$$) of boys and girls in an examination are $$70$$ and $$73$$, respectively. If the mean marks of all the students in that examination is $$71$$, find the ratio of the number of boys to the number of girls.

Standard deviation for first 10  natural numbers is

Let $${ x }_{ 1 },{ x }_{ 2 },.....{ x }_{ n }$$ be $$n$$ observations with mean $$m$$ and standard deviation $$s$$. Then the standard deviation of the observations $$a{ x }_{ 1 },a{ x }_{ 2 },.....a{ x }_{ n }$$, is

Standard deviation for first 10 even natural numbers is

If a variable $$x$$ takes values $$0,1,2,....n$$ with frequencies proportional to the binomial coefficients $${ _{  }^{ n }{ C } }_{ 0 },{ _{  }^{ n }{ C } }_{ 1 },{ _{  }^{ n }{ C } }_{ 2 },......{ _{  }^{ n }{ C } }_{ n }$$, then mean of distribution is