Two numbers are selected at random(without replacement) from the first five positive integers. Let X denote the larger of the two numbers obtained. Find the mean and variance of X

Explanation

It is known that , the first five positive integers arc 1,2,3,4 and 5 .

We can selected two numbers from 5 numbers is


`{ }^{5} P_{2}=frac{underline{5}}{lfloor 5-2}=frac{120}{6}=20 .`


Here, given X denote the larger of two numbers we observe that X can be take values 2,3,4,5.

P(X=2)= Probability that larger number is 2 .

{P}(X=2)= Probability of getting 1 in first selection

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