Probability Distributions: Discrete Random Variables
Submitted by gfj100 on Wed, 11/11/2009  10:39
For a discrete random variable, its
probability distribution
(also called the probability
distribution function) is any table, graph, or formula that gives each possible value and the
probability of that value.
Note
: The total of all probabilities across the distribution must be 1,
and each individual probability must be between 0 and 1, inclusive.
Examples:
(1) Probability Distribution for Number of Heads in 4 Flips of a coin
Heads
0
1
2
3
4
Probability
1/16
4/16
6/16
4/16
1/16
This could be found be listing all 16 possible sequences of heads and tails for four flips, and then
counting how many sequences there are for each possible number of heads.
(2) Probability Distribution for number of tattoos each student has in a population of students
Tattoos
0
1
2
3
4
Probability
0.850
0.120
0.015
0.010
0.005
This could be found be doing a census of a large student population.
Cumulative Probabilities
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '11
 AndyRegards
 Probability, Probability distribution, Cumulative distribution function, heads

Click to edit the document details