KPrep Review12-Random Sampling/Compare Populations

A career counselor at a high school surveys 5 groups of students about their plans after graduation. Each student choses one plan. Each group is a random sample of 25 students. A total of 800 students are in school. The results of the survey are shown in the table. What is likely to be the most common plan among all students in the school?

• The most common plan among the students will likely be to get a job. Approximately 33% of the students surveyed chose this plan. About 264 of the students in the entire school would be estimated to choose this plan.

• The most common plan among the students will likely be to go to college. Approximately 40% of the students surveyed chose this plan. About 320 of the students in the entire school would be estimated to choose this plan.

• The most common plan among the students will likely be to learn a trade. Approximately 44% of the students surveyed chose this plan. About 352 of the students in the entire school would be estimated to choose this plan.

• The most common plan among the students will likely be to be a volunteer. Approximately 50% of the students surveyed chose this plan. About 400 of the students in the entire school would be estimated to choose this plan.

A researcher at a fish hatchery takes three random samples of the same size from a population of 1,200 baby salmon.

-In the first sample, 28% of the salmon are over 2 in. long.

-In the second sample, 32% of the salmon are over 2 in. long.

In the third sample 27% of the salmon are over 2 in. long.

Based on the three samples, how many baby salmon in the population should the researcher expect to be over 2 in. long?

• 324

• 336

• 348

• 384

The owner of a company is ordering t-shirts for all of her 675 employees. She asks 75 randomly selected employees what size they would like. The table shows the results. Based on the data from the sample, determine the true statements about the number of each size t-shirt to order.

• There should be 108 small t-shirts ordered.

• There should be 200 medium t-shirts ordered.

• There should be 261 large t-shirts ordered.

• There should be 110 extra large t-shirts ordered.

A box contains 90 letter tiles used for a word game. Fourteen students each select a random sample of 20 letters from the box, count the vowels, and return the sample to the box. The dot plot shows their results. What is the best estimate for the number of vowels in the box? Round the final answer to the nearest whole number.

• 38.25

• 39

• 38

• 8.5

Anthony selects three random samples of 40 students each and counts how many are wearing shorts to school. The results are shown in the table. Based on the results of Anthony's three samples, what range of inferences is reasonable?

• From 70% to 75% of the school population wore shorts to school.

• From 73% to 80% of the school population wore shorts to school.

• From 75% to 85% of the school population wore shorts to school.

• From 70% to 85% of the school population wore shorts to school.

A meadow filled with white flowers covers 1,000 m² of land. In a random 25-m² area, Hazel counts 300 white flowers. How many flowers are a reasonable estimate of the number of white flowers in the entire meadow?

• 12,000

• 300,000

• 1,200

• 10,000

Kyle takes three random samples of the same size from a populations of 1,500 dog groomers to determine whether they advertise by mail.

-In the first samples, 68% of the dog groomers advertise by mail.

-In the second sample, 70% of the dog groomers advertise by mail.

-In the third sample, 75% of the dog groomers advertise by mail.

Based on the three samples, how many of the dog groomers in the population should Kyle expect to advertise by mail?

• 1020

• 1050

• 1125

• 1065

The owner of a gift shop has decided to start selling locally-made jam. He asks 65 randomly selected customers what flavor they prefer. The table shows the results. The gift shop owner will order 455 jars of jam. Based on the data from the sample, determine which statements about the flavors of the jam are true.

• The order should have 152 jars of strawberry jam.

• The order should have 98 jars of raspberry jam.

• The order should have 154 jars of apricot jam.

• The order should have 75 jars of peach jam.

The bag contains 81 quarters. Twelve students each select a random sample of 16 quarters from the bag, count the number of quarters with a date before 2000, and return the sample to the bag. The line plot shows their results. Which is the best estimate for the number of pre-2000 quarters in the bag, to the nearest whole number?

• 21

• 28

• 30

• 37

Imani selected three random samples of 25 students each and asked them if they walked to school. The results are shown in the table. Based on the results of the three surveys, what range of inferences is reasonable?

• From 44% to 52% of the school population walked to school.

• From 48% to 54% of the school population walked to school.

• From 52% to 56% of the school population walked to school.

• From 44% to 56% of the school population walked to school.