Question 1

The executives of an accounting firm plan to survey a random sample of clients to determine how satisfied they are with the service they have received. Of the firm's 5412 regular clients, 500 are surveyed and 435 claim to be very satisfied with the service they have received. The sample is:

Accepted Answer

A)  the 5412 regular clients. 
B)  the 500 clients surveyed. 
C)  the 435 satisfied clients. 
D)  the 65 clients that were not satisfied.

Question 2

Can we eliminate variability in results of sampling? Why or why not?

Accepted Answer

The answer of Can we eliminate variability in results of...

Question 3

A polling company surveys 200 people outside a county courthouse concerning tighter restrictions on smoking in public buildings. Their results indicate that 34% of those surveyed favor tighter restrictions. The actual proportion of county residents who favor tighter restrictions is 65%. The difference is most likely due to:

Accepted Answer

A)  variability in sampling. 
B)  bias due to the use of a convenience sample. 
C)  confounding variables in the survey. 
D)  the wording of the survey.

Question 4

You must choose a simple random sample of 25 of the 314 members of your fly fishing club. How would you label the population in order to use a table of random digits to make your selection?

Accepted Answer

A)  1, 2, 3, …, 24, 25 
B)  1, 2, 3, …, 313, 314 
C)  001, 002, 003, …, 313, 314 
D)  000, 001, 002, …, 313, 314

Question 5

A survey is sent to 100 employees at a community hospital asking if they support a law requiring motorcycle riders to wear helmets. The results indicate 88% support the law. If the actual proportion of the community's residents who support the law is 72%, the difference is most likely a result of:

Accepted Answer

A)  sampling bias. 
B)  sampling variability. 
C)  an insufficient sample size. 
D)  a poorly worded questionnaire.

Question 6

When variables have effects on the outcome which cannot be distinguished from each other, those variables are said to be:

Accepted Answer

A)  correlated. 
B)  confounded. 
C)  Well designed. 
D)  Dependent.

Question 7

When you estimate a population proportion by sample, quadrupling the sample size:

Accepted Answer

A)  doubles the margin of error. 
B)  halves the margin of error. 
C)  multiplies the margin of error by four. 
D)  divides the margin of error by four.

Question 8

A recent survey of 536 employees of U.S. corporations determined that 84% of them feel that the executives who run their companies are ethical. Determine the 95% confidence interval for this survey.

Accepted Answer

The answer of A recent survey of 536 employees of...

Question 9

A physical education researcher wishes to determine if walking every day affects the health of middle-aged men. The researcher randomly identifies 400 participants in two groups. Members of one group belong to a health club and walk on its track and members of the other do not. After two months, the researcher decides the group who walks daily is healthier and concludes that walking positively affects men's health. This conclusion is of questionable validity because:

Accepted Answer

A)  of the placebo effect. 
B)  of confounding variables in the study. 
C)  the study is not double-blind. 
D)  the researcher is not a doctor.

Question 10

A school principal is concerned with the increasing level of absenteeism in the school. A meeting of parents, teachers, and students is called at which the principal expresses her concern and describes an experimental program that will be instituted to try to curb absenteeism. After two months, absenteeism is down by 15%. Explain how confounding variables may have affected the results of the experiment.

Accepted Answer

The answer of A school principal is concerned with the...

Question 11

A new stadium is being planned for the local professional football team. One of the proposed funding methods involves the allocation of tax monies to build the stadium. To determine the public opinion of this plan, the first 100 people entering the stadium for a game are surveyed. Explain why the results of this survey might not be valid.

Accepted Answer

The answer of A new stadium is being planned for...

Question 12

The Gamma Community College athletic department tests two new logos for the college's athletic teams (call them Modern and Traditional) by showing them to a random sample of 100 Gamma students. Sixty of the 100 prefer Modern. Then the department repeats the test by drawing a new random sample of 100. Again, 60 prefer the Modern logo. Given that 1000 students attend Gamma, this result is:

Accepted Answer

A)  surprising. 
B)  impossible. 
C)  to be expected.

Question 13

You sample all 1000 people in the population of interest and find that $\hat { p }$ is 0.2. Why should you not use the margin of error formula to find a 95% confidence interval for p?

Accepted Answer

The answer of You sample all 1000 people in the...

Question 14

Explain the difference between a parameter and a statistic.

Accepted Answer

The answer of Explain the difference between a parameter and...

Question 15

Beginning with line 104 of the random digits table above, select three individuals to receive a prize in a contest. $$\begin{array} { l l l l } 
01 \text { Anderson } & 06 \text { Hall } & 11 \text { Opus } & 16 \text { Thompson } \
02 \text { Butts } & 07 \text { Hunsaker } & 12 \text { Parson } & 17 \text { Ubet } \
03 \text { Calvin } & 08 \text { Jones } & 13 \text { Quayle } & 18 \text { Watson } \
04 \text { Ernest } & 09 \text { Miller } & 14 \text { Riley } & 19 \text { Wilson } \
05 \text { Gaynor } & 10 \text { Norton } & 15 \text { Stone } & 20 \text { Ziggy }
\end{array}$$

Accepted Answer

A)  Jones, Jones, Ubet 
B)  Hunsaker, Jones, Miller 
C)  Jones, Ubet, Wilson 
D)  Butts, Jones, Ubet

Question 16

Statistical inference refers to methods for drawing conclusions about sample statistics based on the statistical knowledge on the population.

Accepted Answer

A) True 
 B)False

Question 17

A polling company conducted a survey of voters to obtain data for a political campaign. They selected 3500 voters randomly from the 168,000 names on the voter registration lists of the county and found that 1372 intended to vote for candidate Doe. The 168,000 names represent:

Accepted Answer

A)  the population. 
B)  the sample.

Question 18

A telephone survey calls 200 registered voters in Ward 8 and asks them which of two candidates for alderman, Sullivan or Mossman, they prefer. Sixty say Sullivan, 60 say Mossman, and 80 refuse to answer. What is the nonresponse rate?

Accepted Answer

A)  20% 
B)  40% 
C)  60% 
D)  80%

Question 19

A marketing department surveys 1500 shoppers and finds that 950 would visit a new store more often if it was open on Sunday evenings. What is the sample proportion in this survey?

Accepted Answer

The answer of A marketing department surveys 1500 shoppers and...

Question 20

Beginning with line 102 of the random digits table above, select three individuals from the list below to serve on a student affairs committee. $$\begin{array} { l l l l } 
01 \text { Crosby } & 06 \text { Jones } & 11 \text { Turner } & 16 \text { Bush } \
02 \text { Hunter } & 07 \text { Smith } & 12 \text { Baker } & 17 \text { Thompson } \
03 \text { Cooper } & 08 \text { Davis } & 13 \text { Wilson } & 18 \text { Goodman } \
04 \text { Grant } & 09 \text { Ewing } & 14 \text { Adams } & 19 \text { Stevens } \
05 \text { Riley } & 10 \text { Doe } & 15 \text { Hill } & 20 \text { Williams }
\end{array}$$

Accepted Answer

A)  Cooper, Doe, Smith 
B)  Doe, Ewing, Grant 
C)  Doe, Smith, Smith 
D)  Crosby, Ewing, Grant

Exam 7: Data for Decisions