Probability Review #1-10

Jason is conducting an experiment using a bag of marbles. For each trial of the experiment, he takes 1 marble from the bag without looking. He records the color and then replaces the marble in the bag. The table shows the results of 20 trials of the experiment.

Results of Experiment

Blue 10 Green 4 Yellow 6

Jason will conduct 5 more trials of the experiment. Based on the results in the table, how many of those marbles will be green?

• 3

• 1

• 2

• 4

Laura is conducting an experiment in which she draws a straw. Some of the straws are short, and some are long. For each trial, she draws a straw, records the result, and replaces the straw. The table shows the results of 50 trials of the experiment.

Results of Experiment

Long 10 Short 25

Laura will conduct 10 more trials of the experiment. Based on the results in the table, how many of these additional trials will have a result of a Long straw being drawn?

• 3

• 6

• 5

• 2

Each year in middle school, students are randomly assigned to one of 4 electives. The probability of a random student being assigned to each elective is shown below:

Elective Art 0.40

Band .16

Chorus 0.25

Computers ?

If every student is assigned an elective, what is the probability that a student is assigned to computers?

(Hint remember all probabilities each 1)

• .91

• .81

• .75

• 1

At Park Middle School, students have several options for lunch everyday. For the main dish, students can choose from cheese sticks, pizza, hamburger, or soup. For a side item, students can choose an apple, grapes, or side salad. For dessert, students can choose either a yogurt or a cookie. Each student will also receive a carton of low fat milk. How many different variations can students choose for their main dish, side item, dessert and drink? (Draw a tree diagram, or use the counting principle)

• 24

• 36

• 3

• 10

Victoria has a bag with orange, yellow, and blue chips in it. Without looking, she reaches into the bag and removes a chip. She records the color and returns the chip to the bag. Victoria performs this experiment 20 times. The table shows the data she collects.

Chip Experiment

Orange 10

Yellow 6

Blue 4

Based on the information in the table, how many yellow chips should Victoria expect to select out of the bag after repeating this experiment 80 times?

• 40

• 24

• 16

• 30

Shelly recreated an experiment in which the probability of drawing a red card from a stack of red, blue, yellow and purple cards is ¼. She draws a card, records it, replaces it, and then draws another card and continues this procedure 100 times. At the end of her experiment, she notices that she has drawn a red card 33 times. Are Shelly’s results the same, higher or lower than the predicted results?

• same

• higher

• lower

Kevin had 7 nickels 6 dimes and 3 quarters in his pocket. If he took out one coin and then a second coin without replacing the first coin what is the probability that both coins were nickles?

• 6/15

• 42/240

• 7/16

• 7/40

A student is taking a multiple-choice test that has 40 questions. Each question has four answer choices. If the student guesses randomly on every question, how many questions should the student expect to answer correctly?

• 12

• 15

• 10

• 13

The table lists the probability of four events occurring. Which event is least likely to occur?

Event Probability

A 0.70

B. 0.08

C 0.20

D 0.02

• A

• B

• C

• D

A box contains 1 blue marble, 3 red marbles, and 8 green marbles. Is the probability likely, certain, unlikely, or impossible to pick a blue marble without looking?

• Likely

• unlikely

• certain

• impossible

• neither