Sample and Predictions

Making a prediction in statistics is a

• random guess

• 100% accurate fact

• using a magic 8 ball

• using previous information to determine how likely something is to happen

A poll was taken of Hobby Middle School, 25 out of 30 students said they would prefer pizza on Friday’s. Out of 1200 students, what is a reasonable prediction of how many students would prefer pizza on Fridays?

• 100

• 1000

• 10

• 1

Tags

CCSS.6.RP.A.3B

True or False: all samples lead to a good prediction about an entire population.

• True

• False

A principal randomly chooses 40 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 120 students?

• 27

• 9

• 18

• 80

Tags

CCSS.7.RP.A.3

A study on a random sample of 250 cars passing through a toll booth shows that 75 cars are from out of state. Predict the number of out-of-state cars among 1000 cars passing through the toll booth.

• 300

• 250

• 200

• 350

Answer explanation

To predict the number of out-of-state cars among 1000 cars, use the ratio from the sample: 75/250 = x/1000. Solving for x gives 300.

Tags

CCSS.7.RP.A.3

A survey on a random sample of 500 people in a city shows that 250 people use public transportation. Predict the number of people using public transportation if the city's population is 10,000.

• 5000

• 2500

• 7500

• 1000

Answer explanation

To predict the number of people using public transportation in a city with a population of 10,000, we can use the ratio from the sample. 250 people out of 500 use public transportation, so in a population of 10,000, we can expect 5000 people to use public transportation.

Tags

CCSS.7.RP.A.3

A random sample of 200 people at a concert shows that 120 people are wearing hats. Predict the number of people wearing hats if 800 people are at the concert.

• 480

• 320

• 600

• 400

Answer explanation

To predict the number of people wearing hats for 800 attendees, use the ratio of people wearing hats in the sample. 120/200 = x/800. Solving for x gives 480.

Tags

CCSS.7.RP.A.3

In a random sample of 200 seeds, 140 seeds germinated. Predict the number of seeds that would germinate if 1000 seeds were planted.

• 700

• 500

• 600

• 800

Answer explanation

To find the number of seeds that would germinate if 1000 seeds were planted, use the proportion method: (140 seeds germinated / 200 seeds) = (x seeds germinated / 1000 seeds). Solving for x gives 700 seeds germinated.

Tags

CCSS.7.RP.A.3

A random sample of 80 books at a library showed that 32 books were fiction. Predict the total number of fiction books in a library that has 400 books.

• 160

• 200

• 140

• 120

Answer explanation

To find the total number of fiction books in the library, we can set up a proportion: 32 books out of 80 are fiction, so 400 books would have (32/80) * 400 = 160 fiction books.

Tags

CCSS.7.RP.A.3

In a random sample of 30 cookies, 9 cookies have chocolate chips. Predict how many cookies will have chocolate chips if 150 cookies are made.

• 45

• 30

• 60

• 75

Answer explanation

Since 9 out of 30 cookies have chocolate chips, the proportion is 9/30. Applying this proportion to 150 cookies gives 45 cookies with chocolate chips.

Tags

CCSS.7.RP.A.3