Download 04/21/17 Chapter 2 Probability Review

Name: ________________________
Chapter 5 – Probability
Math 7
Chapter Review
Experimental and Theoretical Probability
Probability =
favorable # of outcomes of a particular event(s)
total # of possible outcomes
Remember To Always Reduce Fractions To Lowest Terms!
1)
Sam likes to play hockey and is working on this penalty
shots.
a. What is the theoretical probability that he will make a
penalty shot?
b. In practice, Sam made 19 out of 25 penalty shots. What is
the experimental probability that he will make a penalty shot?
c. What is the experimental probability that he will miss?
d. If Sam continues practicing and makes a total of 100 practice shots, how
many shots would you expect him to make?
2)
A bag contains 7 yellow, 3 green, and 4 blue marbles.
One marble is chosen and
then replaced. Give the probability of each event.
a. P(yellow)
_______
c. P(green or blue) _______
b. P(purple)
_______
d. P(not green) _______
3)
A spinner is divided into five equal sections.
a. What is the theoretical probability of landing on blue?
b. The spinner is spun 45 times and lands on blue 3 times.
How does this compare to the theoretical probability of
spinning blue? *HINT: Did blue happen more or less than expected?
4)
A recent survey was taken to ask people their favorite television station.
Use
the chart below to answer the following questions:
Favorite Television Station
ABC
FOX
MTV
ESPN
WB-11
Number of Respondents
22
16
45
32
10
a) What is the theoretical probability that an individual’s favorite station is FOX?
b) What is the experimental probability that an individual’s favorite station is ABC?
c) What is the experimental probability that an individual’s favorite station is MTV or
WB-11?
Experimental Probability and Making Predictions




Find the experimental probability
Set up a proportion to figure out the prediction
Solve
Label your answer
5) When 100 children were questioned about their reading habits, 71 said they read at
bedtime. If 700 children were questioned, about how many of them would you expect
to read at bedtime?
6) There are 100 kindergarteners in a school. If 3 out of 5 kindergarteners can tie their
shoes, how many kindergarteners can tie their shoes?
Tree Diagrams and The Counting Principle
7)
The employee cafeteria at a certain company offers a choice of the following
cookies with ice cream for dessert.
Cookie
peanut butter
chocolate chip
oatmeal raisin
a. Make a
b.
Scoop of Ice Cream
vanilla
strawberry
mint chip
rocky road
tree diagram and list the possible dessert, you may abbreviate.
If the cafeteria adds a sugar cookie to the cookie choices,
how many possible combinations will there be?
8)
Use the counting principle to find the number of outcomes in each
situation:
a. Books: 3 authors, 2 books by each author
b. Shirts: 4 styles, 2 sizes, 13 colors in each style
c. Bookcases: 20 widths, 3 heights, 5 kinds of wood
d. A pet store sells 3 breeds of dog, each breed in four colors. How many
different dogs do they sell?
Probability: Independent and Dependent events
Probability =
9)
favorable # of outcomes of a particular event(s)
total # of possible outcomes
A coin and a number cube are tossed.
a. What is the probability of the coin landing on tails and the cube being a five?
b. P(Heads and a number divisible by 3)
c. P(Heads and an even number)
d. What is the probability of the coin landing on tails and the cube NOT being a
four?
10) Sally
spins the spinner twice.
What is the probability that it will land on RED both times?
11) A
bag contains 12 marbles: 2 blue, 4 red, 5 orange and 1 white.
You choose
two in a row without replacement. Find:
a. P(blue then red)
b. P(orange then white)
c. P(orange then orange)
d. P(blue then red then white)
12)
A drawer contains 6 socks:
2 blue and 4 red. Johnny is getting ready for
crazy sock day at school and he chooses one sock at random,
does not replace it, and then selects another sock. What is
the probability that he will choose a blue sock and then a red
sock?