HW CH 1
. Only 29% of high school girls are happy with themselves. (Fact: Of 3,000 high school girls, 29% responded "I am happy with the way I am". Most answered "Sort of true" and "Sometimes true." Refer to the study of self-esteem of high school girls. Explain why the results of the study are likely to be misleading. What data might be appropriate for assessing the self-esteem of high school girls? A. The results of the study are likely to be misleading because they do not present all of the data to the public. Data on what girls are unhappy with would be more useful. This is the correct answer.B. The results of the study are likely to be misleading because only 3,000 girls participated. Data on what girls are unhappy with would be more useful. C. The results of the study are likely to be misleading because the girls may not tell the truth. Data on what girls are unhappy with would be more useful. Your answer is not correct.D. The results of the study are not likely to be misleading.
The results of the study are likely to be misleading because they do not present all of the data to the public. Data on what girls are unhappy with would be more useful.
One in four children in a certain country under age 12 is hungry or at risk of hunger. (Fact: Based on responses to questions "Do you ever cut the size of meals" and "Do you ever eat less than you feel you should?") Refer to the food and hunger study of hunger in a certain country. Explain why the results of the study are likely to be misleading. What data would provide insight into the proportion of hungry children? A. The results of the study are likely to be misleading due to nonresponse bias from the ambiguous questions. Data on hunger-related illnesses might provide more insight. B. The results of the study are likely to be misleading due to measurement error from the ambiguous questions. Data on hunger-related illnesses might provide more insight. C. The results of the study are likely to be misleading due to measurement error from ambiguous questions. D. The results of the study are not likely to be misleading.
The results of the study are likely to be misleading due to measurement error from the ambiguous questions. Data on hunger-related illnesses might provide more insight.
b. What are the variables of interest? Are they quanititative or qualitative in nature? A. Prize amountPrize amount, quantitative; Happiness levelHappiness level, qualitative B. Prize amountPrize amount, qualitative; Happiness levelHappiness level, quantitative C. Prize amountPrize amount, qualitative; Happiness levelHappiness level, qualitative D. Prize amountPrize amount, quantitative; Happiness levelHappiness level, quantitative
A
Why would a statistitician consider an inference incomplete without an accompanying measure of its reliability? A. Without a measure of reliability, the statistician does not know how certain the inference is to apply to the population of interest. B. The measure of reliability determines the resource constraints, which determines the sample used in obtaining the statistical data. C. The measure of reliability determines whether the statistician can use inferential or descriptive statistics. D. Without a measure of reliability, the statistician does not know how well their sample represents the population of interest.
A
b. What method was used to collect the sample data? A. The data are from a published source.are from a published source. B. The data were collected observationally.were collected observationally. C. The data are from a designed experiment.are from a designed experiment.
A
c. Describe the population of interest. Choose the correct answer below. A. All lottery winnerslottery winners B. Personal happiness levelsPersonal happiness levels C. Lottery winners from the past two yearsLottery winners from the past two years D. Lottery prize amounts
A
c. Identify the sample. Choose the correct answer below. A. The sample is the 174174 accounting alumni who returned the questionnaire. B. The sample is all accounting alumni of the large university. C. The sample is the 600600 accounting alumni who returned the questionnaire. D. The sample is all alumni of the large university.
A
d. Describe the sample. A. The 3,000 employees surveyed B. All employees in the region C. All people in the region D. The 660 employees who answered yes
A
d. Identify the data-collection method used. Choose the correct answer below. A. The data are from a survey. B. The data are from a published source. C. The data were collected observationally. D. The data are from a designed experiment.
A
e. 30% of employes would "definitely" or "probably" stop offering health coverage to employees if a government-sponsored act were passed. (Fact: Employers were asked leading questions that made it seem logical to them to stop offering insurance.) Refer to the health reform survey. Explain what a "leading question" is and why it might produce responses that bias the results.
A "leading question" is a question that leads the participant to a particular response, producing an outcome desirable to the researcher, leading to biased results.
A popular television program reported on several misleading (and possibly unethical) surveys in a "Fact or Fiction?" segment. The basic results from four of these studies are presented below. Complete parts a through e. a. Eating oat bran is a cheap and easy way to reduce cholesterol count. (Fact: Diet must consist of nothing but oat bran to achieve a slightly lower cholesterol count.) Refer to the study relating oat bran to cholesterol levels. Discuss why it is unethical to report the results as stated. A. It is unethical to report the results as stated because oat bran cannot reduce cholesterol count. B. It is unethical to report the results as stated because they have intentionally selected a nonrandom sample (people who eat only oat bran). C. It is unethical to report the results as stated because exact numerical values are not given. D. It is not unethical to report the results as stated.
B
Explain the difference between qualitative and quantitative data. Quantitative data are data from a population, while qualitative data are data from a sample. B. Quantitative data are numerical in nature, while qualitative data are categorical in nature. C. Quantitative data are data from a sample, while qualitative data are data from a population. D. Quantitative data are collected from an observational study, while qualitative data are from a designed experiment. E. Quantitative data are categorical in nature, while qualitative data are numerical in nature. F. Quantitative data are collected from a designed experiment, while qualitative data are from an observational study.
B
b. What type of data (quantitative or qualitative) is produced by each of the variables measured? A. The quantitative variables are gender, level of education, job satisfaction score, and Machiavellian rating. The qualitative variables are age and income. B. The quantitative variables are age, income, job satisfaction score, and Machiavellian rating. The qualitative variables are gender and level of education. C. The quantitative variables are age, income, and gender. The qualitative variables are level of education, job satisfaction score, and Machiavellian rating. D. The quantitative variables are gender, level of education, and job satisfaction score. The qualitative variables are age, income, and Machiavellian rating.
B
c. Is the variable quantitative or qualitative? A. The variable is a quantitative variable. Its values cannot be expressed on a naturally occurring numerical scale. B. The variable is a qualitative variable. Its values cannot be expressed on a naturally occurring numerical scale. C. The variable is a qualitative variable. Its values can be expressed on a naturally occurring numerical scale. D. The variable is a quantitative variable. Its values can be expressed on a naturally occurring numerical scale.
B
A company surveyed a random sample of 3,000 employees in the region. One question they asked was, "If your employer provides you with mentoring opportunities are you likely to remain in your job for the next five years?" They found that 660 members of the sample said yes. a. Identify the population of interest to the company. A. All people in the region B. The 660 employees who answered yes C. All employees in the region D. The 3,000 employees surveyed
C
A research company performed a study of Machiavellian traits in accountants. Machiavellian describes negative character traits that include manipulation, cunning, duplicity, deception, and bad faith. A questionnaire was administered to a random sample of 600600 acccounting alumni of a large university; however, due to nonresponse and incomplete answers, only 174174 questionnaires could be analyzed. Several variables were measured, including age, gender, level of education, income, job satisfaction score, and Machiavellian ("Mach") rating score. The research findings suggest that Machiavellian behavior is not required to achieve success in the accounting profession. Complete parts a through f. a. What is the population of interest to the researcher? A. All 174174 accounting alumni who returned the questionnaire B. The 600600 accounting alumni C. All accounting alumni of the large university D. All alumni of the large university
C
A study examined the personalthe personal benefitsbenefits of winningwinning thethe lottery.lottery. In the study, the researchers investigated the link between lottery prize amountlottery prize amount and personalpersonal happinesshappiness (measured on a 55-point scale where 1equals="very unhappyvery unhappy" and 55equals="very happyvery happy"). Participants for the study were thosethose who won thewon the lottery withinlottery within the pastthe past two years.two years. The lotterylottery's directory was searched for winnerswinners with "average" names (e.g. "John Smith", "Sara Jones"). These individuals were then invited to participate in an online survey in exchange for a $100100 gift certificate. Of the respondents, those who wonwon thethe largestlargest oror thethe smallestsmallest prizesprizes were excluded, leaving a sample size of 4545 respondents. Answer parts (a) through (d). a. Identify the experimental units for this study. Choose the correct answer below. A. Personal happiness levelsPersonal happiness levels B. All lottery winnerslottery winners C. Lottery winners from the past two yearsLottery winners from the past two years .D. Lottery prize amounts
C
Explain how populations and variables differ. A. A population is a set of units of interest to a study. A variable is an object upon which data is collected. B. A variable is a set of units of interest to a study. A population is a characteristic or property of the units being studied. C. A population is a set of units of interest to a study. A variable is a characteristic or property of the units being studied. D. A population is a set of units of interest to a study. A variable is a subset of the units of a population.
C
c. Is the study an application of descriptive or inferential statistics? Explain. A. The study is an application of descriptive statistics because it uses the sample of 281 third basemen to draw a conclusion about drafting third basemen in general. B. The study is an application of descriptive statistics because it measured different variables for each third baseman and presented the data in a convenient form. C. The study is an application of inferential statistics because it uses the sample of 281 third basemen to draw a conclusion about drafting third basemen in general. D. The study is an application of inferential statistics because it measured different variables for each third baseman and presented the data in a convenient form.
C
d. Do you believe the sample of 4545 respondents is representative of the population? Explain. A. Yes, an average subset of the population was obtained, and anyone within this subset could participate. B. No, although an average subset of the population was obtained, the group within this subset that participated was self-selected. C. No, selection bias is present since only those with "average" names could participate, and the group of these that did was self-selected. D. Yes, since the lotterylottery is popular, the sample is likely to contain a diverse group.
C
e. What inference was made by the researcher? A. A high level of education is important to achieve success in the accounting profession. B. Job satisfaction is important to achieve success in the accounting profession. C. Machiavellian behavior is not required to achieve success in the accounting profession. D. Gender does not have an effect on success in the accounting profession.
C
A study examined the employment benefits of getting a PhD degree.PhD degree. The researchers made inferences based on employment rate data collected for a sample of individuals who took graduate entrance examinations required for PhD program admission.PhD program admission. All those who took exam in any of four selected periods were mailed a questionnaire.Those who responded to the questionnaire were then sent three follow dash up surveys. The final sample of 3 ,853,785 represents only those individuals who responded to all four surveys. (For example, about 6,000 took the exam on one occasion: of these, only about only about 700 responded to to all four surveys.) a. For this study, describe the population of interest. A. All people who have a PhD.All people who have a PhD. B. All 3 comma 785 people who responded to all four surveys.All 3,785 people who responded to all four surveys. C. All people who are employed. D. All those who took the exam during the selected time period.All those who took the exam during the selected time period.
D
b. Based on the question posed by the company what is the variable of interest? A. The number of employees surveyed B. If the employees are provided with mentoring opportunities C. How long the employees are likely to remain in their job D. If they answered yes to the survey question
D
b. What variable is being measured? A. The 7777 million households in the region B. All people in the region who are over 1414 years old C. The 5858,000 households visited in the region D. ImmigrationImmigration status
D
c. Do you think the final sample is representative of the population? Why or why not? Comment on potential biases in the sample. A. YesYes, the data is unbiased because the researchers did not obtain it themselves.the data is unbiased because the researchers did not obtain it themselves. B. NoNo, because the data only covers a limited time.because the data only covers a limited time. C. NoNo, because the data is now outdated.because the data is now outdated. D. YesYes, because the original data wasbecause the original data was randomly sampled.
D
s the following study descriptive or inferential? In a statistical magazine, average professional athletes' salaries in three sports were compiled and compared for the years 1993 and 2003. Is the study descriptive or inferential? A. Descriptive, because the statistics are used to make an estimate of the average salaries of all professional athletes B. Inferential, because the statistics are a summary of the average salaries of professional athletes in three sports C. Inferential, because the statistics are used to make an estimate of the average salaries of all professional athletes D. Descriptive, because the statistics are a summary of the average salaries of professional athletes in three sports
D
b. Domestic violence causes more birth defects than all medical issues combined. (No study - false report). Consider the false domestic violence report on domestic violence and birth defects. Discuss the type of data required to investigate the impact of domestic violence on birth defects. What data-collection method would you recommend? Data measuring the rate of birth defects in people who have not experienced domestic violence versus those who have would be useful. An observational study is recommended. This is the correct answer.B. Data measuring the rate of birth defects in the population and the rate of domestic violence in the population would be useful. A designed experiment is recommended. C. Data measuring the rate of birth defects in people who have not experienced domestic violence versus those who have would be useful. A designed experiment is recommended. D. Data measuring the rate of birth defects in the population and the rate of domestic violence in the population would be useful. A survey is recommended.
Data measuring the rate of birth defects in people who have not experienced domestic violence versus those who have would be useful. An observational study is recommended.
In a baseballbaseball league, the worst-performing teams get the opportunity to select the best third basementhird basemen coming out of college during the draft. A journal collected data for all 281281 third basementhird basemen drafted in the past 40 years as part of a study. Several variables were measured for each third basemanthird baseman, including draft position left parenthesis top 10 comma between 11 dash 50 comma after 50 right parenthesisdraft position (top 10, between 11-50, after 50), heightheight, and production score (higher scores indicate more productive third basemanthird basemans). The researchers discovered that draft positiondraft position is only weakly related to performance. They concluded that "higher draftedhigher drafted third basementhird basemen do not appear to perform any better." Complete parts (a) through (c) below. a. What is the experimental unit for this study? A third baseman A researcher A draft position A baseball team
a third baseman
Is production score a quantitative or qualitative variable? Note that production score is a value calculated from players' statistics to measure their performance. A. Quantitative B. Qualitative
a. quantitative
b. Identify the type (quantitative or qualitative) of each variable measured. Is draft positiondraft position a quantitative or qualitative variable? A. Quantitative B. Qualitative
b. qualitative
Is height a quantitative or qualitative variable? A. Qualitative B. Quantitative
b. quantitative
Each month interviewers visit about 7171,000 of the 9797 million households in the region and question the occupants over 6060 years of age about their retirementretirement status. Their responses enable the interviewers to estimate the percentage of people in the labor force who are retiredretired. Complete parts a through c. a. Define the population of interest to the interviewers. A. All people in the region who are over 6060 years old B. The 7171,000 households visited in the region C. RetirementRetirement status D. The 9797 million households in the region
d
c. Is the problem of interest to the interviewers descriptive or inferential? Descriptive Inferential
infrerential
A company tracked somesome credit card purchases during the year 2005 and measured two variables: (1) the cardholder's gender left parenthesis male or female right parenthesiscardholder's gender (male or female), and left parenthesis 2 right parenthesis the amount left parenthesis in dollars right parenthesis(2) the amount (in dollars)of interest chargedof interest charged. a. Identify the type (quantitative or qualitative) of each variable measured. b. Does the data set collected represent a population or a sample? a. Is the variable (1) qualitative or quantitative? Quantitative Qualitative
qualitative
Is it quantitative or qualitative? Quantitative Qualitative
qualitative
Is the variable (2) qualitative or quantitative? Quantitative Qualitative
quantitative
b. Does the data set collected represent a population or a sample?
sample
