Arithmetic mean of 10 observations is 60 and sum of squares of deviations from 50 is 5000. What is the standard deviation of the observations?

The standard deviation σ of the first N natural numbers can be obtained using which…

A committee of three has to be chosen from a group of 4 men and…

Consider the following in respect of two events A and B : 1.P(A occurs but…

One bag contains 3 white and 2 black balls, another bag contains 5 white and…

A box has ten chits numbered 0, 1, 2, 3, …, 9. First, one chit…