If x̄ and ȳ are the means of two distributions such that x̄ < ȳ and z̄ is the mean of the combined distribution, then which one of the following statements is correct ?

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…

What is the mean deviation about the mean for the data 4, 7, 8, 9,…

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