Name ______Date ______Period ______

Math 7 Unit 6 Probability STUDY GUIDE

1. / Label each event “I” for independent and “D” for dependent
_____ You study Science every night, and then you get an A on the next test.
_____ You draw a card and do not replace it. Then you draw another.
_____ You draw a card from a deck, replace it, and draw a second.
_____ You grab two marbles from a jar at the same time.
2. / A spinner is divided into six sections numbered from 1 to 8. You spin the spinner 41 times. The results are as follows:
Number / 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8
Number of Times Spinner Landed on Number / 2 / 3 / 6 / 5 / 4 / 8 / 11 / 2
Find P(4). Write the probability as a fraction in simplest form and a percent.
3. / You select a marble from a bag containing 22 marbles. The bag contains: 6 blue marbles, 4 green marbles, 7 red marbles, 3 white marbles, and 2 yellow marbles. Find P(not blue).
4. / Your sock drawer contains 2 pairs of gray socks, 6 pairs of white socks, 5 pairs of black socks, and 2 pairs of beige socks. You choose a pair of socks from the drawer at random and then replace it. Then you choose a second pair of socks. Find P(white, then white).
5. / Suppose you spin the spinner below twice. Find P(vowel, then G). All the sections of the spinner are of equal size.
6. / You roll a standard number cube. Find P(number less than 5).
7. / On any given day, the Dairy Crème Cones offers 4 flavors (vanilla, chocolate, strawberry, or the flavor of the day) and 3 toppings (nuts, M&M’s, or peanut butter cups). How many possible choices are there for a Dairy Crème Cones?
8. / Amy has a blue dress, a purple dress, and a yellow dress. For shoes, she can choose dress shoes or sandals. How many different outfits are in the sample space?
9. / George spins the spinner twice. All the sections of the spinner are of equal size. What is the probability that it will land on an odd number both times?
10. / Jessie is going to perform an experiment in which he spins each spinner once. What is the probability that the first spinner will land on B, the second spinner will land on a number less than 4, and the third spinner will land on Green?
Use the spinners below to answer questions 11 and 12.
11. / Mrs. Louis spins each spinner one time. All the sections of the spinner are of equal size. What is the probability that the first spinner will land on an even number and the second spinner will land on B?
12. / What is the probability that the first spinner will land on 8 and the second spinner will land on A?
13. / Place the letter of each event a-f on the scale at the spot that best describes its probability.
A) Your neighbor’s dog has four legs
B) The sun will rise tomorrow
C) You roll a 2 on a number cube
D)You get tails when you toss a coin
E) You run 75 miles in one hour
F) You toss a coin and get two heads
14. / Jaime says that if she rolls two number cubes 36 times, she will get double fours exactly once. Maggie said she cannot be sure this will happen exactly once, but it will probably happen very few times. Who is right? Explain your reasoning.
15. / You can order pants with the three different lengths (shorts, capris, and ankle) and the three different colors (navy, khaki, denim). Draw a tree diagram to show the number of choices.
16. / Suzie has the following items in her book bag:
One purple 12-inch ruler
One blue 12-inch ruler
One pink pen
One blue pen
One purple pen
Sarah will randomly select one 12-inch ruler and one pen. Draw a tree diagram to show all of the possible combinations of one 12-inch ruler and one pen that Sarah could select. What is the probability that Sarah will select a purple 12-inch ruler and either a pink or a blue pen?
17. / Elaine told David that if she rolled a number cube 50 times the probability of getting a product of 31 is zero. David said that she couldn’t be certain that would happen without actually doing the experiment. Who is right? Explain your reasoning.
18. / Sixty percent of blood donors have type A blood. You are going to design a simulation using playing cards to determine how many donors would need to be selected at random before you found one with type A blood. If red cards represent type A blood and black cards represent the other blood types, how many red cards and how many black cards out of ten would be needed in your simulation? Explain.