Transcript Probability

Do Now 5/20/13

Take out HW from the weekend.
 Cumulative

Test Chapters 1-9
Copy HW in your planner.
 Text
p. 408, #1-16
 Text p. 412, #3-10
 Quiz sections 10.1-10.4 Friday

Be ready to copy POTW #8
Learning Goal
SWBAT use informal measures of
probability
SWBAT find experimental probability
Section 10.1 “Probability”
Probabilityis the measure of how likely an event
is to occur.
It is written as P(event). Each
repetition of an experiment is called a
trial. Each result is called an outcome.
“Interpreting Probabilities”

The probability of something occurring is
always between 0 and 1.
Impossible
0
0
0
Unlikely
to occur
0.25
25%
1/4
As likely
as not
Likely
to occur
0.5
50%
1/2
0.75
75%
3/4
Certain to
occur
1
100%
1
Determine whether the event is impossible, unlikely, as
likely as not, likely, or certain.

Flipping a ‘head’ or ‘tail’ on a coin
certain

The temperature will be above 60°F in July.
likely

Rolling a 1, 3, or 5 on a fair dice
as likely as not
COMPLEMENT
The
of an event is the set
of all outcomes that are NOT the event.
If the probability of rolling a 5
with a single dice is
1
,
6
then the probability of NOT
rolling a 5 would be
5.
6
If the probability of rolling a 5
with two dice is
1
9
,
then the probability of NOT
rolling a 5 would be
8.
9
Section 10.2 “Experimental Probability”
Experimental probabilitycomparing the number of times the event
occurs to the number of trials
# of times the event occurs
P
total # of trials
Probability Applications

So far this softball season, Tanya has gotten 8
hits out of 26 at bats. What is the experimental
probability that she will get a hit on her next at
bat? What is Tanya’s batting average?
# of times the event occurs
P
total # of trials
P (hit ) 
8
26
P(hit ) 
4
13
Tanya’s batting
average would be
0.308
Probability Applications

Pam is playing darts. She hit the bull’s eye 7
times out of 20 throws. What is the experimental
probability that Pam will hit the bull’s eye on her
next throw as a fraction and percent? What is
the experimental probability that she will NOT hit
the bull’s eye?
# of times the event occurs
P
total # of trials
7
P(bull ' s eye) 
20
35%
P( NOT bull ' s eye) 
65%
13
20
“Experimental Probability”
Draw the following circle chart on
your paper. Shade in the blue
areas on your chart with your
pencil.
Using your pencil and a paperclip
spin your spinner 8 times. Record
the number of times where
the spinner stopped.
Do your experimental outcomes
match the theoretical outcomes?
Why or why not?
Homework
Text
p. 408, #1-16
Text p. 412, #3-10