Unit 5 Inferences Review

Anthony wants to find out the percentage of students at his school who are vegetarians. Which of the following is the most representative group of students for him to survey?

• 50 students at an ice-cream parlor

• 5 students at an ice-cream parlor

• 50 students at a hamburger restaurant

• 5 students at a hamburger restaurant

Customers at a fast-food restaurant were invited to complete a brief survey to rate their experiences at the restaurant. One day, 48 customers chose to complete the survey. Which statement best explains why this was probably NOT a representative sample?

• The sample size was too small.

• The sample size was too large.

• The sample included only those people who chose to complete the survey.

• The sample included only those people who were customers at the restaurant.

Lakeesha wants to find out what percentage of the people in her town speak more than one language. Which is the best group of people for her to survey?

• 100 people who are enrolled in a Spanish class

• 100 people randomly selected from the telephone book

• 100 people who answer an advertisement in the newspaper

• 100 people randomly selected from the local university faculty

An advertising company claims that its surveys make valid generalizations about the people it surveys. Which of the following is the most important consideration for the people the company selects to survey?

• The people must be relatively easy for the company to contact.

• The people must be a small enough group that they can answer questions quickly.

• The people must be a representative sample of the population.

• The people must volunteer for the survey.

A restaurant offers three types of meats: chicken, beef, and pork. The waiters surveyed 50 customers at random about their favorite type of meat. The results are listed on the graph. If the restaurant orders 400 pieces of meat,___________ pieces will be chicken.

• 25

• 100

• 200

• 375

200 teenagers were surveyed to determine where they get the majority of their news information. The following results were obtained:

89 from social media

54 from television

40 from online news websites

17 from print newspapers or magazines

Part A:

Based strictly on this survey, how many teenagers out of 100,000 get the majority of their news information from television?

Part B:

Based only on this survey, could we determine that 20% of people between the ages of 13 and 25 get the majority of their news information from online news websites? Why or why not?

• 27,000/Yes, the survey could determine that 20% of people between the ages of 13 and 25 get a majority of their news from online news websites.

• 2,700/Yes, the survey could determine that 20% of people between the ages of 13 and 25 get a majority of their news from online news websites.

• 2,700/No, the survey is not representative sample because it only includes teenagers.

• 27,000/No, the survey is not representative sample because it only includes teenagers.

Each student in Mrs. Halstead’s class was assigned a random group of 10 seventh graders. They asked everyone in each group the following question: “Do you prefer vanilla or chocolate ice cream?” The results of some of the students' findings are shown below.

Marcy’s group: 4 vanilla and 6 chocolate

Owen’s group: 3 vanilla and 7 chocolate

Steve’s group: 1 vanilla and 9 chocolate

Vivian’s group: 2 vanilla and 8 chocolate

When the class combined all of the results, they found that 110 seventh graders preferred vanilla and 190 preferred chocolate. Which student’s results were closest to the class results?

• Marcy

• Owen

• Steve

• Vivian

Which of the following would produce a sample that would be representative of a school's seventh–grade population?

• surveying every fifth seventh grader in a pre–algebra class

• surveying every fifth seventh grader in the library

• surveying every fifth seventh grader entering the school at the beginning of the school day

• surveying every fifth seventh grader in the cafeteria in one of the school's three lunch periods

The principals at 5 middle schools asked their teachers if they preferred a shorter work day or a shorter school year. Afterward, Mr. Howard asked the same question of some of the teachers at his school.

Of the 500 teachers in the principals’ survey, 220 said they preferred the shorter work day.

Of the 10 teachers in Mr. Howard’s survey, 4 said they preferred the shorter school year.

Which statement best explains why Mr. Howard’s results are different from the principals’ results?

• Mr. Howard used teachers from his school that were already in the principals’ survey.

• Mr. Howard did not ask the principals what they thought of their results.

• Mr. Howard used fewer teachers in his survey than the principals did.

• Mr. Howard did not make sure to ask teachers in only one grade level.

Each student in a first-grade classroom checked out a book at the school library. The teacher recorded the number of words on the first page of each of those books, as shown in this table.

The school librarian chooses a children’s book at random from the shelf. Based on the sample, what is the most likely mean number of words on the first page?

• 4

• 5

• 8

• 7