Download Name 8-1 Notes IB Math SL Lesson 8

Name ___________________________
8-1 Notes
IB Math SL
Lesson 8-1 Probability Distributions
Learning Goa ls: What are the properties of Probability distributions.
Random variables
Probability Distributions
A probability distribution/probability model is a table/chart that displays
_________________________ along with their _____________________
__________________. A probability model has two parts:
1) A list of _______________________________________________ and
2) The probability that ______________________________________________.
The Probability distribution of a discrete random variable can be given in:



Graphical form
Table form
In functional form as a probability mass function.
Example: If you are rolling a die
X=
P(x)
1
2
3
4
5
6
The value we summarize in a probability distribution is called a
_______________________________. This is a variable whose possible values represent the
possible outcomes of an experiment, usually in a probability distribution.
Notation:
We use a _________________________________, like X or Y, to denote a random
variable.
A specific value of a random variable will be denoted with a lower case letter, in this
case x.
Properties of Random Variables:
Since we are talking about variables and their probabilities the same 2 cardinal rules still
hold:
1.
2.
Class Data: Data will be collected by each member of the class. Each student will share out the
total number of biological siblings they have. Let the random variable X represent the number
of siblings each student has.
a)
What are the possible values that the random variable X can possibly take on? Is this a
discrete or continuous random variable?
b)
What are the values that the random variable X has taken on?
c)
Draw the probability distribution
d)
Find P( X  1) .
e)
Find P( X  2) .
f)
Find P( X  3) .
g)
Find P( X  2) .
Using the Properties of probability distributions to help us solve!
1.
Property used:
2.
Property used:
3.
Property used:
4. Tabulate the probability distributions for each:
a. The number of sixes that are obtained when two ordinary dice are thrown
b. The product of the faces when two ordinary dice are thrown.
Practice time!
1.