CHAPTER 3
MEASUREMENTS, MISTAKES, AND MISUNDERSTANDINGS
SECTION 3.1
SIMPLE MEASURES DON’T EXIST
FREE RESPONSE QUESTIONS
1. Explain why even the simplest kind of measurement, such as finding your height, still presents complicated issues.
ANSWER: ANY REASONABLE ANSWER OK. EXAMPLES: THE ACCUR...
1. Name one way in which the study of statistics is useful for every day life.
ANSWER: ANY REASONABLE ANSWER OK. EXAMPLES: WEATHER
PREDICTION, POLLS/SURVEYS, TEST SCORES, ETC.
2. Statistics is about collecting information and using it to help you make a decision. Give an
example of a decision that could be made using statistics.
ANSWER: ANY REASONABLE ANSWER OK. EXAMPLES: SHOULD I TAKE AN
UMBRELLA TO SCHOOL TOMORROW? IS THE BANK GOING TO BE BUSY
TODAY? WHAT IS THE MOST POPULAR TV SHOW THIS WEEK?
3. Name one way that you have used statistics in your own life.
ANSWER: ANY REASONABLE ANSWER OK. EXAMPLES: TO DECIDE WHAT
BRAND OF COMPUTER TO BUY, I CONSULTED STATISTICS FROM CONSUMER
REPORTS; TO DECIDE WHICH APARTMENT TO RENT, I LOOKED AT THE
RECENT CRIME STATISTICS FROM THE POLICE DEPARTMENT.
4. While you can learn a lot about the world just by observing it, you can learn even more by
conducting a carefully controlled experiment involving statistics. Explain why.
ANSWER: A CONTROLLED EXPERIMENT ALLOWS YOU TO MAKE CAREFUL
COMPARISONS TO FIND OUT IF DIFFERENCES REALLY DO EXIST, AND IF SO,
TO ATTRIBUTE A CAUSE FOR THE DIFFERENCE.
MULTIPLE CHOICE QUESTIONS
5. Which of these does not apply to the word ‘statistics’?
a. Statistics are numbers measured for some purpose.
b. Statistics is a collection of procedures for collecting and analyzing data.
c. Statistics is a tool to help you make decisions when faced with uncertainty.
d. All of the above apply to the word ‘statistics’.
ANSWER: D
6. Which of the following is not an example of a situation involving statistics?
a. A pie chart showing the percentage of males and females in your class.
b. A designed experiment comparing the heights of left-handed vs. right-handed people.
, c. A survey asking your opinion of whether or not college football players should be paid to
play football.
d. All of the above are examples of situations involving statistics.
ANSWER: D
7. Which of the following questions cannot be addressed using statistics?
a. What percentage of people in the U.S. are cell phone owners?
b. Which of these two medicines has a better success rate at lowering cholesterol?
c. Do mothers most often hold their babies in their arms so the baby is on the left side?
d. All of the above can be addressed using statistics.
ANSWER: D
8. Which of the following is not true about the subject of statistics?
a. Statistics only represents numbers that are used for a specific purpose.
b. Statistics is a collection of procedures and principles for dealing with information.
c. Statistics appears in your every day life.
d. Statistics has a great deal to do with decision making in the face of uncertainty.
ANSWER: A
FILL-IN-THE-BLANK QUESTIONS
9. __________ is a collection of procedures and principles for gaining and analyzing information in
order to help people make decisions when faced with uncertainty.
ANSWER: STATISTICS
10. Statistics is a collection of procedures and principles for gaining and analyzing information in
order to help people make decisions when faced with __________.
ANSWER: UNCERTAINTY
SECTION 1.3
DETECTING PATTERNS AND RELATIONSHIPS
FREE RESPONSE QUESTIONS
11. Explain the difference between the statistical terms ‘population’ and ‘sample'.
ANSWER: THE POPULATION IS THE ENTIRE GROUP FOR WHICH YOU PLAN TO
DRAW CONCLUSIONS. THE SAMPLE IS THE GROUP THAT IS ACTUALLY
STUDIED, AND IS CHOSEN FROM THE POPULATION.
12. Suppose you want to determine whether taking vitamins every day helps people lose weight. You
survey 200 people who had been on a weight loss program for six months, and ask them whether
or not they take vitamins every day, and how much weight they lost. Suppose you found that the
people who lost the most weight were more likely to have taken vitamins every day. Does this
mean vitamins caused the additional weight loss? Explain why or why not.
ANSWER: NO; THIS WAS AN OBSERVATIONAL STUDY, NOT A CONTROLLED
EXPERIMENT. OTHER FACTORS COULD EXPLAIN THE WEIGHT LOSS, SUCH AS
, A HEALTHY LIFESTYLE (PEOPLE WHO ARE HEALTH CONSCIOUS MAY BE
MORE LIKELY TO TAKE VITAMINS).
13. Suppose you participate in an ‘instant poll’ on an Internet website which asks, “What is your
favorite network TV program at 8 pm (Eastern time) on Thursday night?” After answering the
question, you look at the results of the entire poll, and find that 6,423 people have responded to it.
Should the results of this poll be a good indicator of what the most popular network TV program
is on Thursday nights at 8pm (Eastern time)? Explain why or why not.
ANSWER: NO. THE SAMPLE OF 6,423 PEOPLE IS A CONVENIENCE SAMPLE, AND
IS NOT A REPRESENTATIVE SAMPLE OF THE POPULATION OF ALL TV
WATCHERS.
14. Suppose researchers who conduct a vitamin study conclude in an evening news sound byte that
“Daily vitamin use is good for everyone.” You get a copy of the study they referred to, and find
that the participants were all healthy young males who exercised regularly. Explain why the
headline is misleading from a statistical standpoint.
ANSWER: THE CONCLUSION IN THE HEADLINE SHOULD NOT REFER TO
EVERYONE. THE RESULTS ONLY APPLY TO HEALTHY YOUNG MALES WHO
EXERCISE REGULARLY.
MULTIPLE CHOICE QUESTIONS
For Questions 15-16, use the following narrative
Narrative: Babysitting
Suppose a recent study of 1,000 teenagers in the U.S. found that 33% of them do babysitting to earn
extra money.
15. {Babysitting Narrative} Which of the following describes the population for this example?
a. All teenagers in the U.S.
b. The 1,000 teenagers who participated in the study.
c. All teenagers in the U.S. who do babysitting for extra money.
d. The 33% of teenagers who do babysitting to earn extra money.
ANSWER: A
16. {Babysitting Narrative} Which of the following describes the sample for this example?
a. All teenagers in the U.S.
b. The 1,000 teenagers who participated in the study.
c. All teenagers in the U.S. who do babysitting for extra money.
d. The 33% of teenagers who do babysitting to earn extra money.
ANSWER: B
17. Which of the following statements is true?
a. The more variable the groups within a population are, the larger the sample needs to be to
detect any real difference between the groups.
b. The more variable the groups within a population are, the smaller the sample needs to be
to detect any real difference between the groups.
c. No matter how variable the groups within a population are, the size of the sample needed
to detect a real difference between the groups is the same.
d. None of the above statements are true.
ANSWER: A
18. Which of the following is necessary to conduct a study properly?
a. Get a representative sample.
b. Get a large enough sample.
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