7Th Grade/Unit 6 Probability

Name: ______Date:______Period:____

7th Grade/Unit 6 Probability Study Guide

1. A bag contains 3 red, 1 yellow, and 5 green marbles. Without looking, you choose a marble from the bag. What is true about the probability of selecting a yellow marble from the bag? The probability is closer to 0? ½? or 1?

2. Darius is on the basketball team. He has a 75% free throw rate. He may complete his next free throw. Describe a method that could be used to simulate this situation?

3. In one hour yesterday, 3 out of every 7 milkshakes sold was chocolate. Based on the findings, how many chocolate shakes can we expect to sell if 392 shakes are sold?

4. A pizza shop has 2 meat toppings, 3 vegetable toppings, and 3 cheese toppings. How many different pizzas (one meat, one vegetable, and one cheese topping) can be made?

5. There’s a sticky spot on the floor. Eight out of thirteen people had their shoes stick while walking by. Approximately, what’s the probability, in percents, that the next person will also have sticky shoes?

6. You forgot to do the homework for class and the teacher is calling on students to review the answers! If there are 32 students in the class, what is the probability, in percents, that you’ll be called on next?

7. Marla’s cat meows almost every time another cat walks by. For the last twelve minutes, 18 cats have passed and she’s meowed at 15 of them. What’s the likelihood, in percents, that she will NOT meow at the next cat?

8. There are 5 boys and 4 girls from the seventh grade and 3 boys and 7 girls from eighth grade on the war ball team. Coach Downs will pick one captain from each grade. What is the probability, in fractions, that both captains will be boys? 9. A vase has 3 pink flowers, 3 purple flowers, and 6 yellow flowers. Ann took a flower, smelled it, returned it to the vase, and chose another flower. What is probability, in fractions, that the first flower was purple and the second flower was yellow?

10. The probability for a rolling a 3 on a die and getting tails on a coin is. Based on this probability, how many possible outcomes are there? Is it likely that one would roll a 3 and get tails?

11. Armando tosses a number cube with six faces numbered 1 to 6. If Armando does this 160 times, how many times would you expect the cube to land on an even number?

12. There are three different choices for lunch today in the cafeteria. Students may choose spaghetti, chicken sandwich, or tuna salad. Erin can’t decide what she wants to eat. Describe a method that could be used to simulate this situation?

13. The probability of spinning red on the spinner on the right is ¼. Mark spins the spinner 12 times and never gets red. What could be a reason that the theoretical probability (1/4) and the experimental probability (0/12) do not match? 14. Give a fraction to represent a probability that is most likely to occur, but not certain.

15. Amy has five shirts (blue, white, red, yellow, and purple) and four pairs of pants (black, white, grey, and brown) in her closet. The chart below shows the different outfits she can make with these options.

What is the probability that she will end up an outfit that does NOT include the colors red or white?

16. Seth’s team has won 1 out of the last 7 soccer games. How likely is it that they will win again based on this record?

17. Look at the following spinners. What is the probability of spinning a red on the first spinner and a 5 on the second spinner?

18. Three dozen doughnuts contain 4 lemon filled, 6 chocolate filled, 8 banana crème, 4 jelly filled, and 2 vanilla filled. If the doughnuts look identical, what is the probability, in fractions, that if you pick a doughnut at random, it will NOT be lemon or jelly filled? Write your answer as a fraction, decimal and percent.

19. Julie’s team averages 3 homeruns out of every 14 hits per game. Using this information, make a prediction about how many homeruns they can expect after hitting the ball 420 times for the entire season. Show your calculations below.

20. A new restaurant has opened and they offer lunch combos for $7.00. With the combo meal you get 1 sandwich, 1 side and 1 drink. The choices are below.

Sandwiches: Roast Beef, Ham, Turkey, or Tuna

Sides: Chips, Potato Salad, or Slaw

Drinks: Soda or Tea

A. Draw a tree diagram to show the total possible outcomes. B. How many outcomes are possible?

C. If one more drink choice was added, how would that affect the number of outcomes?