Compound Probability and Probability Review

Review: If an event has a theoretical probability of 80%, then we can say that it...

• will definitely occur

• is impoossible

• is unlikely to occur

• is likely to occur

Answer explanation

If an event has a theoretical probability of 80%, it is likely to occur as the probability is high, indicating a greater chance of the event happening.

Tags

CCSS.7.SP.C.5

Review: Using theoretical probability, if I flip a coin 10 times, how many times should I get heads?

• 1

• 10

• 3

• 5

Answer explanation

Using theoretical probability, if a coin is fair, the chance of getting heads is 0.5. Therefore, in 10 flips, you would expect to get heads 5 times on average.

Tags

CCSS.7.SP.C.6

Review: Jillian rolled a number cube 60 times. About how many times do you expect her to roll a 2 based on theoretical probability?

• 20 

• 30

• 10

• 120

Answer explanation

Based on theoretical probability, the expected number of times to roll a 2 in 60 rolls is 1/6 of 60, which is 10 times.

Tags

CCSS.7.SP.C.6

Review: Find the theoretical probability of P(not red) if you spin the spinner.

• 1/8

• 7/8

• 1

• 7

Answer explanation

The theoretical probability of P(not red) is the probability of landing on any color that is not red. Since there are 7 non-red colors out of 8 total colors on the spinner, the probability is 7/8.

Tags

CCSS.7.SP.C.7B

Review (Experimental probability): A principal randomly chose 20 students from grade 5. Of these students, 9 were wearing watches. Based on this information, what is the most reasonable prediction of the number of students wearing watches in a group of 60 students from grade 5? Use a proportion to help you solve!

• 27

• 9

• 18

• 80

Answer explanation

Since 9 out of 20 students wore watches, the proportion suggests that approximately 27 out of 60 students in a larger group would be wearing watches (9/20 = x/60, x = 27). Therefore, the most reasonable prediction is 27 students.

Tags

CCSS.7.SP.A.2

Review: (Experimental probability) At an assembly, 7 out of the first 10 students who entered the gym were carrying a backpack. Based on this information, if 100 students were at the assembly, how many students could be expected to be carrying a backpack?

• 140

• 400

• 350

• 70

Answer explanation

Since 7 out of the first 10 students had backpacks, the experimental probability is 7/10. Extrapolating to 100 students, 70 students can be expected to have backpacks.

Tags

CCSS.7.SP.C.6

An event that consists of two or more events

•  event

• dependent events

• experiment

• compound event

Answer explanation

A compound event is an event that consists of two or more events occurring together. It is the correct choice in this scenario.

The cafeteria is serving three kinds of sandwiches:  tuna (T), chicken, (C), and peanut butter (P).  They are also serving a choice of two drinks:  milk (M) or water (W).  Which shows the CORRECT Sample Space List of possible combinations?

• TW, CW, PW

• TW, TM, TC, CW, PW

• TW, TM, CW, CM, PW, PM

• TCP, MW

Answer explanation

The correct choice is TW, TM, CW, CM, PW, PM as it includes all possible combinations of sandwiches and drinks.

Tags

CCSS.7.SP.C.8B

You roll a six-sided number cube two times. How many outcome combinations are possible? (For example: 1 and 6 is one outcome) Make a tree diagram to help you!

• 6

• 12

• 36

• 18

Answer explanation

The total number of outcome combinations is 36, as there are 6 possibilities for the first roll and 6 for the second, resulting in 6x6=36 combinations.

Tags

CCSS.7.SP.C.8B

Sebastian tosses a coin three times. What is the probability he tosses two heads and one tail (not necessarily in that order)? Make a tree diagram to help you!

• 1/8

• 3/8

• 1/2

• 1/4

Answer explanation

The probability of tossing two heads and one tail is 3/8. The tree diagram would show the different outcomes leading to this result

Tags

CCSS.7.SP.C.8B