AnswersStatistics and ProbabilitySampling and Experimentation

Sampling and Experimentation — Test Answers

25 verified answers
1
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Using the dotplot and the difference in mean distances from the samples, is there convincing evidence that the new golf ball travels farther than the original golf ball?

A
No, because a difference in mean distances of 2 point 6 feet or more occurred 34 out of 200 times, meaning the difference is not statistically significant. There is not convincing evidence the new golf ball travels farther than the original golf ball.
B
Yes, because a difference in mean distances of 2 point 6 feet or less occurred 166 out of 200 times, meaning the difference is statistically significant. There is convincing evidence the new golf ball travels farther than the original golf ball.
C
Yes, because a difference in mean distances of 2 point 6 feet or more occurred only 34 out of 200 times, meaning the difference is statistically significant. There is convincing evidence the new golf ball travels farther than the original golf ball.
D
No, because a difference in mean distances of 2 point 6 feet or less occurred 166 out of 200 times, meaning the difference is not statistically significant. There is not convincing evidence the new golf ball travels farther than the original golf ball.
2
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Which statement is a reasonable explanation for this relationship?

A
People who commit crimes cannot afford to buy more expensive homes.
B
People are less likely to commit crimes if home prices are higher.
C
People who can afford higher home prices are more likely to commit crimes.
D
People are more likely to spend more money on a home if there is a lower crime rate.
3

Which of the following would benefit this experiment the most?

A
This experiment should be single blind. The subjects do not know which treatment they are receiving to control for the placebo effect, but the technicians need to know which group received which treatment.
B
This experiment should be double blind. Neither the subject nor the technician should know which group is receiving the new medication and which is receiving the placebo. This method would control for the placebo effect and prevent any effect on the response.
C
This experiment should be single blind. The subjects know which treatment they are receiving but the technicians do not know which group received which treatment, so the response being measured is not affected.
D
This experiment should not use blinding. It is unethical for the subjects not to know which treatment they are receiving, placebo or new medication, and for the technicians not to know which group received which treatment.
4

City planners plan to survey residents to estimate the proportion of city residents who use public transportation at least once a week. Which of the following methods describes a voluntary response survey?

A
City planners take a random sample of local homes and survey the residents.
B
City planners hand out surveys to parents at a youth soccer game.
C
City planners stand outside an office building and survey workers.
D
City planners email a survey to all residents in the community.
5

A greenhouse owner wants to test the effectiveness of a new fertilizer on African violets. She has 60 violet seedlings that were grown for 8 weeks. She wants to test the new fertilizer on 10 of the plants, and decides to use a simple random sample to select them. Which of the following statements is true?

A
She needs to select the 10 biggest plants to test the new fertilizer.
B
She needs to put the plants in 6 groups of 10 and randomly select 1 of the groups.
C
She needs to number each plant 1–60 and randomly select 10 plants.
D
She needs to select the 10 smallest plants to test the new fertilizer.
6

A city official would like to know if there is public support for increasing funding for arts programs. To collect data, the city official stands outside a concert hall after a show and surveys every 25th person to exit and asks their opinion about raising funds for the arts. Which of the following describes the population in this scenario?

A
the members of the city council
B
all city residents who support the arts
C
all residents of the city
D
the people surveyed by the city official
7

A citizen wants to propose to the city council extending the hours at the local public library on some weekdays. To measure support for extended hours, the citizen visits neighborhood homes and asks adults the following: "Would you agree that the closing time of the library should be extended by one hour on weekdays to accommodate working families?” Of the 212 adults surveyed, 86 percent agreed with the statement. Which of the following statements about the results is true?

A
The survey suffers from voluntary response bias and may not estimate true support for the extended hours.
B
The survey suffers from question wording bias and may not represent true support for the extended hours.
C
The 86 percent support provides substantial evidence that the library hours should be extended.
D
More families should be asked the same question to be sure of community support.
8

An automotive service center would like feedback on its customer service. Each customer receives a printed card after they pay for services with a short survey on which customer service is ranked on a scale from 1 (least satisfied) to 5 (most satisfied). Customers can then choose to submit the card in a box on their way out of the store. The store manager finds that 140 cards were filled out in the past week, with an average customer satisfaction score of 2 point 4 7 Which type of bias is most likely to be present in the survey results?

A
This is response bias because customers may not be truthful about their experience with customer service.
B
This is nonresponse bias because many customers may choose to not fill out the cards.
C
This is question wording bias because the customer service score levels may not be clear to customers.
D
This is undercoverage bias because some types of customers may not have received cards.
9

Several members of a running club would like to survey the rest of the members to determine which 5K races the club should enter. They decide to use a random number table to sample 10 of the 78 members. The members are assigned the numbers 01–78. Refer to the given line from a random number table. Which numbers represent the first 5 members selected? 24000 75983 62200 91518 11198 88936

A
24, 07, 59, 62, 20
B
24, 75, 98, 36, 22
C
24, 75, 36, 22, 51
D
24, 00, 07, 59, 83
10

A teacher has 36 students who are sitting in 6 rows of 6 desks. He wants to survey the students about the homework policy. Which of the following uses cluster sampling?

A
List all of the students alphabetically. Survey 1 randomly chosen student whose last name begins with A , then continue the process through the alphabet.
B
Randomly assign the students to desks, and number the students 01–36. Use a random number table to generate a sample of students.
C
List all of the students alphabetically. Survey the 2nd person (with the number 2 being randomly chosen), then survey every 5th student after that.
D
Randomly assign the students to desks. Number the rows 1 to 6. Use a random number table to select a number from 1 to 6, then survey every student in that row.
11

Race organizers want to survey the participating runners on the quality of the running course. Which of the following uses systematic random sampling?

A
Select the first 15 finishers and the last 15 finishers to take the survey.
B
Select the 5th finisher (with the number 5 being randomly chosen) to survey, then survey every 15th finisher after that.
C
Sort all of the runners’ names alphabetically, then randomly choose 2 letters and survey all participants whose last name begins with one of those letters.
D
Randomly select 15 percent of the male participants and 15 percent of the female participants.
12

A factory produces plastic parts used to fit in car dashboards. It is important that the parts are produced with the correct dimensions, or they may not fit in the car dashboard. To ensure that the parts are being made correctly, a sample of parts is checked and measured each day. Which of the following methods would not represent a convenience sample?

A
The first 20 parts produced after the start of the day are inspected and measured.
B
Right after lunch, the first 25 parts are inspected.
C
Fifty parts are chosen at random from the many parts made each day.
D
At the end of the day, a container of 30 parts is inspected and measured.
13

Education researchers are interested in the workload expectations of freshmen at a local university. Which of the following techniques would give a stratified random sample?

A
Randomly select 10 freshmen from the cafeteria on each of the 5 days of the first school week.
B
Survey the students in some randomly selected freshman seminar classes, since freshmen are randomly put into those classes.
C
Randomly select 10 freshmen from each of the majors at the university.
D
Randomly select 1 professor at the university and have them survey all of their freshman students.
14

Which of the following is a valid conclusion?

A
Inferences can be made about the population of fabric from which the pieces were cut. The conclusion can be made that detergent A cleans better than detergent B for the fabric from these bolts.
B
Inferences cannot be made about the population of fabric from which the pieces were chosen. The conclusion cannot be made that detergent A cleans better than detergent B for the fabric from these bolts.
C
Inferences can be made about the population of fabric from which the pieces were cut. The conclusion cannot be made that detergent A cleans better than detergent B for the fabric from these bolts.
D
Inferences cannot be made about the population of fabric from which the pieces were cut. The conclusion can be made that detergent A cleans better than detergent B for the fabric from these bolts.
15

Which of the following accurately describes the benefit of comparison in the experiment shown in the design web?

A
The level of allergic symptoms in both groups can be compared to see if the new medication had a significant effect.
B
The level of allergic symptoms in both groups cannot be compared to determine if the medication had a significant effect because one group only received a placebo.
C
The overall level of allergic symptoms can be used to determine if the new allergy medication had a significant effect.
D
The level of allergic symptoms in the group who received the medication can be used to determine if the medication had a significant effect.
16

Does this procedure describe a completely randomized design for this experiment?

A
Yes, the treatment groups have the same number of dogs.
B
No, the names were taken in order, so there was no randomization.
C
No, the veterinarian did not use dogs of the same breed.
D
Yes, the treatments were randomly assigned to the dogs.
17

Which number range would be needed to label the subjects correctly?

A
000–210
B
0–2
C
001–210
D
1–3
18

Using this dotplot and the difference in proportions from the samples, is there convincing evidence that the new additive was more effective?

A
Yes, because a difference in proportions of 0 point 4 or less occurred 193 out of 200 times, meaning the difference is statistically significant and the new additive is more effective.
B
No, because a difference in proportions of 0 point 4 or less occurred 193 out of 200 times, meaning the difference is not statistically significant and the new additive is not more effective.
C
No, because a difference in proportions of 0 point 4 or more occurred 7 out of times, meaning the difference is not statistically significant and the new additive is not more effective.
D
Yes, because a difference in proportions of 0 point 4 or more occurred 7 out of 200 times, meaning the difference is statistically significant and the new additive is more effective.
19

Which of the following is the best description of the experimental design?

A
observational study
B
matched pairs design
C
randomized block design
D
completely randomized design
20

Which method describes an experiment?

A
Method B is an experiment because every car receives the additive.
B
Method A is an experiment because the additive is used with a new tank of gasoline.
C
Method A is an experiment because random assignment determines which cars receive the additive and which cars do not.
D
Both methods are experiments because the additive is used in a new tank of gas in both methods.

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