Name: ______Date: ______
Statistics –Biased VS. Unbiased Samples and Misleading GraphsClass: Pre-Algebra
1 / Determine whether the conclusion is valid. Justify your answer. A radio station asks its listeners to indicate their preference for one of two candidates in an upcoming election. Seventy-two percent of the listeners who responded preferred candidate A, so the ratio station announced that candidate A would win the election. Is the conclusion valid?2 / Determine whether the conclusion is valid. Justify your answer. Every tenth student who walked into the cafeteria was surveyed to determine his or her favorite lunch. Out of 40 students, 19 students stated that they liked the burgers best. The staff concluded that about 50% of the students like burgers best. Is the conclusion valid?
3 / Zach is trying to decide which of three golf courses is the best. He randomly surveyed 25 people at a sports store and recorded the results in the table. Is the sample method valid? If so, suppose Zach surveyed 150 people. How many people would be expected to vote for Rolling Meadows?
4 / The graph suggests that Cy Young had three times as many wins as Jim Galvin. Is this a valid conclusion? Explain.
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/ 5 / The graph below shows the results of a survey to determine students’ favorite pets. Why is the graph misleading?
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6 / To determine how often his students are tardy, Mr. Kessler considered the attendance record for his first period class. Why is this graph misleading?
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7 /
How could the wording of a question or the tone of voice of the interviewer affect a survey? Provide an example.
8 /
How is using a survey one way to determine experimental probabilities?
9 /
Determine whether each statement is sometimes, always, or never true. Justify your answer.
Part A: A biased sample is valid.
Part B: A simple random sample is valid.
Part C: A voluntary response sample is valid.
10 /
Each of the graphs below shows the distance Romerio travels on his bike. Romerio wants to impress his friends with the distance he travels. Which graph should he show his friends? Explain.
11 / Marisol wants to determine how many students plan to attend the girls’ varsity basketball game. Find her mistake and correct it.
/ 12 / The graphs below show the same data.
Part AMatch each graph with the conclusion it leads to.
Conclusion A: Rent has increased dramatically.
Conclusion B: Rent has remained fairly stable.
Conclusion: ______/
Conclusion: ______
Part BIf you were the landlord, which graph would you show potential tenants to try to influence their decision to rent the apartment?
13 / Which of the following samples will be most representative of an entire student population?
A / Surveying every fifth seventh-grader who enters the library
B / Surveying every fifth student who enters the library
C / Surveying every fifth student who enters the school
D / Surveying every fifth girl who enters the school
14 / Morgan surveyed all the members of her softball team about their favorite sport. From these results, Morgan concluded that softball was the favorite among all her classmates. Which is the best explanation for why her conclusion might not be valid?
A / The softball team meets only on weekdays.
B / She should have asked only people who do not play sports.
C / The survey should have been done daily for a week.
D / The sample was not representative of all of her classmates.
15 / The bar graph shows the average number of hours each week that a group of students attend an extracurricular activity after school. Which statement best tells why the graph may be misleading?
/ A / The vertical scale should show days instead of hours.
B / The graph does not show the number of hours each person attended.
C / The intervals on the vertical scale are inconsistent.
D / The graph’s title is misleading.