Chapter 1.1-1.3

A polling company reported that 27% of 1013 surveyed adults said that pesticides are "very harmful." Complete parts​ (a) through​ (d) below. a. What is the exact value that is 27% of 1013​? The exact value is ________. ​(Type an integer or a​ decimal.) b. Could the result from part​ (a) be the actual number of adults who said that pesticides are "very harmful"? Why or why​ not? A. Yes, the result from part​ (a) could be the actual number of adults who said that pesticides are "very harmful" because the results are statistically significant. B. No, the result from part​ (a) could not be the actual number of adults who said that pesticides are "very harmful" because a count of people must result in a whole number. C. ​No, the result from part​ (a) could not be the actual number of adults who said that pesticides are "very harmful" because that is a very rare opinion. D. Yes, the result from part​ (a) could be the actual number of adults who said that pesticides are "very harmful" because the polling numbers are accurate. c. What could be the actual number of adults who said that pesticides are "very harmful"? The actual number of adults with this opinion could be __________. ​(Type an integer or a​ decimal.) d. Among the 1013 ​respondents, 435 said that pesticides are "not at all harmful." What percentage of respondents said that pesticides are "not at all harmful"? __________ %

273.51; B; 274; 42.94%

In the data table​ below, the​ x-values are the weights​ (in pounds) of cars and the​ y-values are the corresponding highway fuel consumption amounts​ (in mi/gal). Weight (lb): 4064, 3335, 4109, 3699, 3590 Highway Fuel Consumption (mi/gal): 25, 31, 29, 28, 30 Comment on the source of the data if you are told that car manufacturers supplied the values. Is there an incentive for car manufacturers to report values that are not​ accurate? A. Yes, because​ consumers, in​ general, would prefer to buy a car with a higher level of fuel efficiency. In this​ case, the source of the data would be suspect with a potential for bias. B. ​No, because​ consumers, in​ general, do not care about the weight of their car. In this​ case, the source of the data would not be suspect and there would be no potential for bias. C. No, because​ consumers, in​ general, would prefer to buy a car with a higher level of fuel efficiency. In this​ case, the source of the data would not be suspect and there would be no potential for bias. D. Yes, because​ consumers, in​ general, do not care about the weight of their car. In this​ case, the source of the data would be suspect with a potential for bias.

A

In the data table​ below, the​ x-values are the weights​ (in pounds) of cars and the​ y-values are the corresponding highway fuel consumption amounts​ (in mi/gal). Weight​ (lb): 4095, 3381, 4166, 3673, 3582 Highway Fuel Consumption (mi/gal): 25, 32, 29, 28, 30 Given the context of the car measurement​ data, what issue can be addressed by conducting a statistical analysis of the​ values? Is there a relationship or an association between the weight of a car and its fuel consumption​ amount? A. Is there a relationship or an association between the weight of a car and its fuel consumption​ amount? B. Is there a relationship between the mean weight of a car and the mean fuel consumption of​ cars? C. Does the highway fuel consumption of a car cause the weight of the car to increase or​ decrease? D. Does the weight of a car cause the highway fuel consumption of the car to increase or​ decrease? E. No conclusion can be drawn from the data.

A

Refer to the given table of measurements below. Is there some meaningful way in which the IQ scores are matched with the corresponding brain​ volumes? If they are​ matched, does it make sense to use the difference between each IQ score and brain volume that is in the same​ column? Why or why​ not? Is there some meaningful way in which the IQ scores are matched with the corresponding brain​ volumes? A. Yes, each IQ score is matched with the brain volume in the same​ column, because they are measurements obtained from the same person. B. No, each IQ score is not matched with the brain volume in the same​ column, because the sample size is too small. C. Yes, each IQ score is matched with the brain volume in the same​ column, because high IQ is caused by large brain volume. D. No, each IQ score is not matched with the brain volume in the same​ column, because high IQ is not caused by large brain volume. If they are​ matched, does it make sense to use the difference between each IQ score and brain volume that is in the same​ column? Why or why​ not? A. No, it does not make sense to use the difference between each IQ score and brain volume in the same​ column, because IQ scores and brain volumes use different units of measurement. B. Yes, it does make sense to use the difference between each IQ score and brain volume in the same​ column, because they are measurements obtained from the same person. C. No, it does not make sense to use the difference between each IQ score and brain volume in the same​ column, because the terms should be added. D. Yes, it does make sense to use the difference between each IQ score and brain volume in the same​ column, because high IQ is caused by large brain volume. E. The data are not matched.

A; A

Based on a study of heights of men and women who play basketball​, a researcher concludes that the exercise from playing basketball causes people to grow taller. Do you agree with this​ conclusion? Choose which conclusion you agree with. A. Yes. People who exercise grow stronger bones and are more likely to grow taller. B. No. There may be a relationship between height and playing basketball, but that does not mean that one causes the other. C. No. There is no relationship between height and playing basketball. D. Yes. People who play basketball need to be tall, so they have evolved with a height advantage.

B

Determine whether the source given below has the potential to create a bias in a statistical study. Washington University obtained word counts from the most popular novels of the past five years. Choose the correct answer below. A. There does appear to be a potential to create a bias. There is an incentive to make the results statistically insignificant. B. There does not appear to be a potential to create a bias. The organization would not gain from putting a spin on the results. C. There does appear to be a potential to create a bias. There is an incentive to produce results that are in line with the​ organization's creed and that of its funders. D. There does not appear to be a potential to create a bias. The organization is reputable and has many professional and credible members.

B

What is a voluntary response​ sample? A. A sample in which the sample size is very large. B. A sample in which the researchers decide which subjects to include in the study. C. A sample in which the subjects themselves decide whether to be included in the study. D. A sample in which the response​ "No Opinion" or​ "Not Applicable" are choices.

C

Determine whether the results below appear to have statistical​ significance, and also determine whether the results have practical significance. In a study of a weight loss​ program, 7 subjects lost an average of 46 lbs. It is found that there is about a 20% chance of getting such results with a diet that has no effect. Does the weight loss program have statistical​ significance? A. ​Yes, the program is statistically significant because the results are unlikely to occur by chance. B. Yes, the program is statistically significant because the results are likely to occur by chance. C. No, the program is not statistically significant because the results are likely to occur by chance. D. No, the program is not statistically significant because the results are unlikely to occur by chance. Does the weight loss program have practical​ significance? A. Yes, the program is practically significant because the results are too unlikely to occur by chance. B. No, the program is not practically significant because the results are likely to occur even if the weight loss program has no effect. C. No, the program is not practically significant because the amount of weight lost is trivial. D. Yes, the program is practically significant because the amount of lost weight is large enough to be considered practically significant.

C; D

Determine whether the sampling method described below appears to be sound or is flawed. In a survey of 784 ​subjects, each was asked how often he or she played sports. The survey subjects were internet users who responded to a question that was posted on a news website. Choose the correct answer below. A.It is flawed because it is a census. B. It is flawed because it is not statistically significant. C. It appears to be sound because the data are not biased in any way. D. It is flawed because it is a voluntary response sample.

D

Determine whether the sampling method described below appears to be sound or is flawed. In a survey of 549 human resource​ professionals, each was asked about the importance of the age of a job applicant. The survey subjects were randomly selected by pollsters from a reputable market research firm. Choose the correct answer below. A. It is flawed because it is a voluntary response sample. B. It is flawed because it is not statistically significant. C. It is flawed because it is a census. D. It appears to be sound because the data are not biased in any way

D

Determine whether the source given below has the potential to create a bias in a statistical study. A certain medical organization tends to oppose the use of meat and dairy products in our​ diets, and that organization has received hundreds of thousands of dollars in funding from an animal rights foundation. A. There does not appear to be a potential to create a bias. The organization is reputable and has many professional and credible members. B. There does appear to be a potential to create a bias. There is an incentive to make the results statistically insignificant. C. There does not appear to be a potential to create a bias. The organization would not gain from putting spin on the results. D. There does appear to be a potential to create a bias. There is an incentive to produce results that are in line with the​ organization's creed and that of its funders.

D

Determine whether the results appear to have statistical​ significance, and also determine whether the results appear to have practical significance. In a study of a gender selection method used to increase the likelihood of a baby being born a​ girl, 2093 users of the method gave birth to 1022 boys and 1071 girls. There is about a 15​% chance of getting that many girls if the method had no effect. Because there is a 15% chance of getting that many girls by​ chance, the method ______________. _________ couples would likely use a procedure that raises the likelihood of a girl from the approximately​ 50% rate expected by chance to the ____​% produced by this method. ​(Round to the nearest integer as​ needed.) So this method _____________.

does not have statistical significance; Not many; 51%; does not have practical significance