What is the mean deviation about the mean for the data 4, 7, 8, 9, 10, 12, 13, 17 ?

A fair coin is tossed four times. What is the probability that at most three…

Two students X and Y appeared in an examination. The probability that X will qualify…

The variance of 20 observations is 5. If each observation is multiplied by 2, then…

If x̄ and ȳ are the means of two distributions such that x̄ < ȳ…

There are 4 white and 3 black balls in a box. In another box, there…