IXL - Write a discrete probability distribution (Geometry practice)

Raymond found out the number of members in all the clubs at his school.

Number of members	Number of clubs
8	5
30	2
72	3

is the number of members that a randomly chosen club has. Write the probability distribution of

in the table below.

Write each probability as a decimal.

X	P ( X )
8
30	0.2
72	0.3

ref_doc_title.

Learn with an example

question

Bruce, a journalism student, counted the number of pages in several major magazines.

Number of pages	Number of magazines
67	4
81	2
114	4

is the number of pages that a randomly chosen magazine had. Write the probability distribution of

in the table below.

Write each probability as a decimal.

X	P ( X )
67
81	0.2
114	0.4

key idea

A random variable is a function that assigns a numerical value to each outcome in a sample space. Note that though random variables are functions, they are usually denoted by letters like

is a random variable,

(

)

(

)

is the probability that

takes the value

The function that maps

(

)

is the probability distribution of

A probability distribution is frequently represented as an equation, table, or graph.

A uniform probability model is a sample space in which all outcomes are equally likely.

In a uniform probability model, the probability of an event

is the number of outcomes in that event divided by the total number of outcomes in the sample space:

(

)

# of outcomes in

total # of outcomes

solution

Each magazine is equally likely to be chosen. So, to find the probability that a magazine that had a particular number of pages is chosen, divide the frequency of that number of pages by the total number of magazines.

Count the total number of magazines.

Add the frequencies of each number of pages to find the total number of magazines:

Write the probability distribution of

Divide each frequency by 10 to find the probability that a magazine chosen at random had a particular number of pages.

X	P ( X )
67	0.4
81	0.2
114	0.4

Looking for more? Try this:

$Confetti$

Excellent!

Now entering the Challenge Zone—are you ready?

Questions
answeredQuestions

Time
elapsedTime

hr	min	sec
00	00	02

SmartScore
out of 100
IXL's SmartScore is a dynamic measure of progress towards mastery, rather than a percentage grade. It tracks your skill level as you tackle progressively more difficult questions. Consistently answer questions correctly to reach excellence (90), or conquer the Challenge Zone to achieve mastery (100)! Learn more

Teacher tools

Work it out

Not feeling ready yet? This can help:

Probability of simple events and opposite events

Excellent! You got that right!

Jumping to level 1 of 1

Excellent!