 # Discrete Random Variables

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More Lessons for A Level Maths
Math Worksheets

A collection of videos, activities and worksheets that are suitable for A Level Maths.

What is the meaning of Var(X) and how to calculate it for a discrete random variable?

The Expected Mean E(X)
The meaning of this function, Expected Mean E(X), and how to use it to calculate the expected mean for a discrete random variable.
Extending E(X) to E(X ± a) and E(aX)
What these functions mean, and how to use them.

Variance : Var(X)
The meaning of Var(X) and how to calculate it for a discrete random variable. Extending Var(X) to Var(X ± a) and Var(aX)
I show you what these functions mean, and how to use them. Why does Var(a)=0, Var(X ± a) = Var(X) and Var(aX) = a2Var(X)?
Non formal proof of these results.

The meaning and calculation of E(X2)
In this tutorial I show you the meaning of this function and how to calculate it for a discrete random variable.

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