Lesson: Standard Deviation of Discrete Random Variables

Mathematics

In this lesson, we will learn how to calculate the standard deviation of discrete random variables.

Plan

Objectives

Students will be able to

calculate the standard deviation of a discrete random variable from a table,
calculate the standard deviation from a probability distribution function of a discrete random variable,
calculate the standard deviation of a discrete random variable from a graph or a word problem describing a real-world system,
calculate the coefficient of variation of a discrete random variable from a table,
calculate the coefficient of variation from a probability distribution function of a discrete random variable,
calculate the coefficient of variation of a discrete random variable from a graph or a word problem describing a real-world system,
find unknowns where the standard deviation or coefficient of variance is given.

Prerequisites

Students should already be familiar with

discrete random variables,
the probability distribution function of a discrete random variable,
the expected value of a discrete random variable.

Exclusions

Students will not cover

standard deviation or variance of a data set,
continuous probability distributions.

Explainer

Sample Question Videos

04:30
03:29
02:49

Worksheet

Q1:

The function in the given table is a probability function of a discrete random variable . Find the standard deviation of . Give your answer to two decimal places.

Q2:

The function in the given table is a probability function of a discrete random variable . Find the standard deviation of . Give your answer to two decimal places.

	4	6	10

Q3:

The function in the given table is a probability function of a discrete random variable . Given that the expected value of is 6.5, find the standard deviation of . Give your answer to two decimal places.

	3		6	8
	0.2	0.1	0.1	0.6

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