Statistics

d

(c) Explain how different measures may be used to support two completely different positions. Choose the correct answer below. A. Values can be left out of the graph so that the graph supports the position. B. Data can be rearranged on the graph to make the graph support any position. C. The data collected can be changed so that it will support the position. D. The scales used in the graph can significantly affect the message.​ Also, the variable used to convey the message on the graph can make a large difference as well.

quantitative

A _________ variable is required when drawing a​ time-series plot.

number

A frequency distribution lists the ______________ of occurrences of each category of​ data

b

A polling organization conducts a study to estimate the percentage of households that have pets. It mails a questionnaire to 1898 randomly selected households across the country and asks the head of each household if he or she has pets. Of the 1898 households​ selected, 37 responded. ​(a) Which of these best describes the bias in the​ survey? a Sampling bias b Nonresponse bias c Response bias d Undercoverage bias

d

A polling organization conducts a study to estimate the percentage of households that have two incomes. It mails a questionnaire to 18061806 randomly selected households across the country and asks the head of each household if he or she has two incomes. Of the 1806 households​ selected, 11 responded. ​(a) Which of these best describes the bias in the​ survey? a. Undercoverage bias b Sampling bias c Response bias d Nonresponse bias

permutation

A(n) _________ is an ordered arrangement of r objects chosen from n distinct objects without repetition.

individual

A(n) _________ is a person or object that is a member of the population being studied.

A

According to a center for disease​ control, the probability that a randomly selected person has hearing problems is 0.1450.145. The probability that a randomly selected person has vision problems is 0.0910.091. Can we compute the probability of randomly selecting a person who has hearing problems or vision problems by adding these​ probabilities? Why or why​ not? Choose the correct answer below. A. ​No, because hearing and vision problems are not mutually exclusive.​ So, some people have both hearing and vision problems. These people would be included twice in the probability. B. ​Yes, because this is an application of the Addition Rule for Disjoint Events. C. ​Yes, because hearing and vision are two different​ senses, and​ therefore, they are two unique problems. D. ​No, because hearing problems and vision problems are events that are too similar to one another.

A

Define simple random sampling. Choose the correct answer below. A. A sample of size n from a population of size N is obtained through simple random sampling if every possible sample of size n has an equally likely chance of occurring. The sample is then called a simple random sample. B. Simple random sampling is the process of using chance to select individuals from a population to be included in the sample. The sample is then called a simple random sample. C. Simple random sampling is the process of selecting individuals from a population using a convenient sample. The sample is then called a simple random sample. D. Simple random sampling is the process of obtaining a sample of size n from a population of the same size n. The sample is then called a simple random sample.

interval

Determine the level of measurement of the variable below. "time of day in military time"

b

Determine the level of measurement of the variable below. Eye color Choose the correct answer below. A. Ordinal B. Nominal C. Ratio D. Interval

A

Determine the level of measurement of the variable below. Nation of origin Choose the correct answer below. A. Nominal B. Ordinal C. Ratio D. Interval

true

Determine whether the following statement is true or false. ​Generally, the goal of an experiment is to determine the effect that the treatment will have on the response variable. Choose the correct answer below. true false

A

Determine whether the following statement is true or false. Explain. Inferences based on voluntary response samples are generally not reliable. Choose the correct answer below. A. ​True, because it is often the case that the individuals who volunteer do not accurately represent the population. B. ​True, because the group that volunteers may not be a large enough sample size. C. ​False, because individuals who volunteer are least likely to have personal bias. D. ​False, because a surveyor cannot force volunteers to respond.

B

Determine whether the following statement is true or false. Explain. When conducting a cluster​ sample, it is better to have fewer clusters with more individuals when the clusters are heterogeneous. Choose the correct answer below. A. False. It is better to have fewer clusters when the clusters are homogeneous. B. ​True, because when the clusters are​ heterogeneous, they are scaled down versions of the population. C. ​True, because heterogeneous clusters are not likely to resemble population​ heterogeneity, increasing the number of necessary individuals. D. ​False, because the proportion of individuals per cluster to the population should not be affected by whether or not the clusters are heterogeneous.

C

Determine whether the following statement is true or false. Explain. When obtaining a stratified​ sample, the number of individuals included within each stratum must be equal. Choose the correct answer below. A. False. A stratified sample is constructed by successively selecting a stratum at random and then selecting a random individual from within that stratum. With this​ process, it is unlikely that all strata will be sampled from the same number of times. B. False. When taking a stratified​ sample, a simple random sample is drawn from one stratum at random. All other strata will not be included in the sample. C. False. Within stratified​ samples, the number of individuals sampled from each stratum should be proportional to the size of the strata in the population. D. True. Sampling the same number of people from each stratum will result in a sample that is representative of the population at a lower cost than a simple random sample.

B

Determine whether the following statement is true or false. Explain. When obtaining a stratified​ sample, the number of individuals included within each stratum must be equal. Choose the correct answer below. A. False. A stratified sample is constructed by successively selecting a stratum at random and then selecting a random individual from within that stratum. With this​ process, it is unlikely that all strata will be sampled from the same number of times. B. False. Within stratified​ samples, the number of individuals sampled from each stratum should be proportional to the size of the strata in the population. C. True. Sampling the same number of people from each stratum will result in a sample that is representative of the population at a lower cost than a simple random sample. D. False. When taking a stratified​ sample, a simple random sample is drawn from one stratum at random. All other strata will not be included in the sample.

C

Determine whether the following statement is true or false. Explain. When taking a systematic random sample of size​ n, every group of size n from the population has the same chance of being selected. Choose the correct answer below. A. ​True, because since k is chosen​ randomly, every group has an equal chance of selection. B. ​True, because any random sampling implies every group has an chance of selection. C. ​False, because certain groups would never be selected. D. ​False, because a systematic sample requires a frame

d

Determine whether the quantitative variable is discrete or continuous. Weight of gravel in a pile Is the variable discrete or​ continuous? A. The variable is discrete because it is not countable. B. The variable is discrete because it is countable. C. The variable is continuous because it is countable. D. The variable is continuous because it is not countable.

D

Discuss the advantages and disadvantages of each type of question. A. Closed questions are harder to​ analyze, because they limit the responses. Open questions allow respondents to state exactly how they​ feel, but are easier to analyze due to the variety of answers. B. Closed questions are easier to​ analyze, because they usually gather more accurate data. Open questions limit the​ responses, but are harder to analyze since not every viewpoint will be covered. C. Closed questions allow respondents to state exactly how they​ feel, but are harder to analyze due to the variety of answers and possible misinterpretation of answers. Open questions are easier to​ analyze, but limit the responses. D. Closed questions are easier to​ analyze, but limit the responses. Open questions allow respondents to state exactly how they​ feel, but are harder to analyze due to the variety of answers and possible misinterpretation of answers.

c

Distinguish between nonsampling error and sampling error. Choose the correct answer below. A. Nonsampling error is the error that results from the process of obtaining the data. Sampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. B. Nonsampling error is the error that results because a sample is being used to estimate information about a population. Sampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. C. Nonsampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. Sampling error is the error that results because a sample is being used to estimate information about a population. D. Nonsampling error is the error that results from randomness. Sampling error is the error that results from using a sample to estimate information about a population.

A

Distinguish between nonsampling error and sampling error. Choose the correct answer below. A. Nonsampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. Sampling error is the error that results because a sample is being used to estimate information about a population. B. Nonsampling error is the error that results because a sample is being used to estimate information about a population. Sampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. C. Nonsampling error is the error that results from the process of obtaining the data. Sampling error is the error that results from​ undercoverage, nonresponse​ bias, response​ bias, or​ data-entry errors. D. Nonsampling error is the error that results from randomness. Sampling error is the error that results from using a sample to estimate information about a population.

B

Does the level of octane in gasoline affect gas​ mileage? To answer this​ question, an automotive engineer obtains 75 cars. Twenty-five of the cars are​ compact, 25 are full​ size, and 25 are sport utility vehicles​ (SUVs). Design an experiment for the engineer. What type of experimental design should the engineer​ use? A. Matched pair B. Randomized block design C. Completely randomized design D. ​Case-control

d

Explain what each point on the​ least-squares regression line represents. Choose the correct answer below. A. Each point on the​ least-squares regression line represents the​ y-value of the data set at that corresponding value of x. B. Each point on the​ least-squares regression line represents one of the points in the data set. C. Each point on the​ least-squares regression line represents the​ y-values that would be considered ideal at that corresponding value of x. D. Each point on the​ least-squares regression line represents the predicted​ y-value at the corresponding value of x.

combination

Fill in the blank. A​ ________ is an arrangement of r objects chosen from n distinct objects without repetition and without regard to order.

multipication

Fill in the blank. The word and in probability implies that we use the​ ________ rule.

quartiles

Fill in the blank. ​_______ divide data sets in fourths.

False

Identify the given statement as either true or false. The standard deviation is a resistant measure of spread. Choose the correct answer below. True False

inferential

If a polling organization claimed that the results of the survey indicate that 77​% of adults in the country believe that the action is acceptable in certain​ situations, would you say this statement is descriptive or​ inferential? Why? The statement is __________ because it makes a prediction.

A

If the linear correlation between two variables is​ negative, what can be said about the slope of the regression​ line? Choose the correct answer below. A. Negative B. Positive C. More information is needed

one

In a relative frequency​ distribution, what should the relative frequencies add up​ to?

D

In their​ report, the researchers stated that​ "After adjusting for various demographic and lifestyle​ variables, daily consumption of two or more servings was associated with a​ 30% reduced prevalence of high cholesterol​." Why was it important to adjust for these​ variables? A. The researchers wanted to ensure that the sample was large enough in order to perform inference. B. The researchers were sure that various demographic and lifestyle variables had greater influence than daily consumption of two or more servings. C. The researchers wanted to ensure that the study was representative of the entire​ population, so they were likely to adjust the responses to match actual data collected for the entire population. D. The researchers may be concerned with confounding that occurs when the effects of two or more explanatory variables are not separated or when there are some explanatory variables that were not considered in a​ study, but that affect the value of the response variable.

d

Inferences based on voluntary response samples are generally not reliable. Choose the correct answer below. A. ​True, because the group that volunteers may not be a large enough sample size. B. ​False, because a surveyor cannot force volunteers to respond. C. ​False, because individuals who volunteer are least likely to have personal bias. D. ​True, because it is often the case that the individuals who volunteer do not accurately represent the population.

experiment

In​ probability, a(n)​ ________ is any process that can be repeated in which the results are uncertain.

explanatory variable

In​ research, one attempts to determine how varying the amount of an _____ ______ affects the value of a response variable. This manipulated variable is the variable that is under the control of the experimenter.

true

Is the following statement true or​ false? When plotting an​ ogive, the plotted points have​ x-coordinates that are equal to the upper limits of each class.

true

Is the statement below true or​ false? The​ least-squares regression line always travels through the point (x,y.) Choose the correct answer below. True False

c

Researchers wanted to determine if having a computer in the bedroom is associated with obesity. The researchers administered a questionnaire to 353353 ​twelve-year-old adolescents. After analyzing the​ results, the researchers determined that the body mass index of the adolescents who had a computer in their bedroom was significantly higher than that of the adolescents who did not have a computer in their bedroom. What is the explanatory​ variable? A. The explanatory variable is the number of the adolescents who have a computer in their bedroom. B. The explanatory variable is the body mass index of the adolescents. C. The explanatory variable is whether the adolescent has a computer in the bedroom or not. D. The explanatory variable is the number of the adolescents who participate in the study.

c

Researchers wanted to determine if having a computer in the bedroom is associated with obesity. The researchers administered a questionnaire to 353353 ​twelve-year-old adolescents. After analyzing the​ results, the researchers determined that the body mass index of the adolescents who had a computer in their bedroom was significantly higher than that of the adolescents who did not have a computer in their bedroom. What is the response variable in the​ study? Is the response variable qualitative or​ quantitative? A. The response variable is the number of the adolescents who have a computer in their bedroom. The response variable is quantitative. B. The response variable is whether the adolescent has a computer in the bedroom or not. The response variable is qualitative. C. The response variable is the body mass index of the adolescents. The response variable is quantitative. D. The response variable is the number of the adolescents who participate in the study. The response variable is quantitative.

a

Researchers wanted to determine if having a computer in the bedroom is associated with obesity. The researchers administered a questionnaire to 353353 ​twelve-year-old adolescents. After analyzing the​ results, the researchers determined that the body mass index of the adolescents who had a computer in their bedroom was significantly higher than that of the adolescents who did not have a computer in their bedroom. What type of observational study is​ this? ​a. Cross-sectional study ​b. Case-control study c. Cohort study

B

Researchers wanted to determine if there was an association between daily kale consumption and the occurrence of high cholesterol. The researchers looked at 94,180 women and asked them to report their kale​-eating habits. The researchers also determined which of the women had high cholesterol. After their​ analysis, the researchers concluded that consumption of two or more servings of kale per day was associated with a reduction in high cholesterol. What is the explanatory​ variable? A. The explanatory variable is the number of individuals who participate in the study. B. The explanatory variable is consumption of kale C. The explanatory variable is the number of individuals who participate in the study who eat two or more servings of kale per day. D. The explanatory variable is whether the woman has high cholesterol or not.

B

Researchers wanted to determine if there was an association between daily kale consumption and the occurrence of high cholesterol. The researchers looked at 94,180 women and asked them to report their kale​-eating habits. The researchers also determined which of the women had high cholesterol. After their​ analysis, the researchers concluded that consumption of two or more servings of kale per day was associated with a reduction in high cholesterol. What is the response variable in the​ study? Is the response variable qualitative or​ quantitative? A. The response variable is the number of individuals who participate in the study who eat two or more servings of kale per day. The response variable is quantitative. B. The response variable is whether the woman has high cholesterol or not. The response variable is qualitative. C. The response variable is consumption of kale. The response variable is quantitative. D. The response variable is the number of individuals who participate in the study. The response variable is quantitative.

B

Researchers wanted to determine if there was an association between daily kale consumption and the occurrence of high cholesterol. The researchers looked at 94,180 women and asked them to report their kale​-eating habits. The researchers also determined which of the women had high cholesterol. After their​ analysis, the researchers concluded that consumption of two or more servings of kale per day was associated with a reduction in high cholesterol. What type of observational study was​ this? Explain. A. This was a cohort study because it identified a group of individuals to participate in the study and observed the group over a long period of time. B. This was a​ cross-sectional study because all information about the individuals was collected at a specific point in time. C. This was a​ case-control study because individuals that had a certain characteristic were matched with those that did not.

a

Select all the reasons why​ time-series plots are used. A. ​Time-series plots are used to identify trends in the data over time. B. ​Time-series plots are used to present the relative frequency of the data in each interval or category. C. ​Time-series plots are used to examine the shape of the distribution of the data. D. ​Time-series plots are used to identify any outliers in the data.

no

Suppose that a probability is approximated to be zero based on empirical results. Does this mean that the event is​ impossible? Yes No

a

Suppose you are conducting a survey regarding illicit drug use among nurses in a city. You obtain a cluster sample of 13 hospitals within a city and sample all nurses in the randomly selected hospitals. The survey is administered by the hospital administration. Which of these best describes the bias in the​ survey? a Response bias b Sampling bias c Nonresponse bias d Undercoverage bias

a

Suppose you are interested in comparing brand A interior latex paint to brand B interior latex paint. Design an experiment to determine which paint is better for painting bathrooms. Choose the best design for this experiment. A. ​Matched-pairs design because experimental units are paired up and there are only two levels of treatment. B. Completely randomized design because experimental units are paired up and there are only two levels of treatment.

b

Suppose you are interested in comparing brand A interior enamel paint to brand B interior enamel paint. Design an experiment to determine which paint is better for painting kitchens. Choose the best design for this experiment. A. Completely randomized design because experimental units are paired up and there are only two levels of treatment. B. ​Matched-pairs design because experimental units are paired up and there are only two levels of treatment.

A

Surveys tend to suffer from low response rates. Based on past​ experience, a researcher determines that the typical response rate for an​ e-mail survey is 2020​%. She wishes to obtain a sample of 150 respondents, so she​ e-mails the survey to 1500 randomly selected​ e-mail addresses. Assuming the response rate for her survey is 20​%, will the respondents form an unbiased​ sample? Explain. Is the sample​ unbiased? A. No. The survey still suffers from undercoverage​ (sampling bias), nonresponse​ bias, and potentially response bias. B. Yes. The number of respondents will be approximately 300​, that​ is, two times greater than the needed size of the sample. C. Yes. The sample was a randomly selected group of​ e-mail addresses, which does not introduce bias. D. No. The survey was not given to the entire population.

upper

The lower class limit is the smallest value within the class and the _______________ class limit is the largest value within the class.

response variable

The ______ _______ is a quantitative or qualitative variable that represents the variable of interest.

lower

The _______ class limit is the smallest value within the class and the upper class limit is the largest value within the class.

c

The cumulative relative frequency for the last class must always be 1.​ Why? Choose the correct answer below. A. All the observations are less than the last class. B. The last class must always have at least one value in it. C. All the observations are less than or equal to the last class.

left

The data are skewed _____ if the median is greater than the​ mean

addition

The word or in probability implies that we use the _________ Rule.

z score

The​ _______ represents the number of standard deviations an observation is from the mean.

class width

The​ _________________ is the difference between consecutive lower class limits.

D

To determine customer opinion of their food quality​, General Foods randomly selects 140 city blocks during a certain week and surveys all homes within the city blocks. What type of sampling is​ used? A. Stratified B. Simple random C. Systematic D. Cluster E. Convenience

D

To help assess student learning in her music theory ​courses, a music professor at a community college implemented​ pre- and​ post-tests for her music theory students. A​ knowledge-gained score was obtained by taking the difference of the two test scores. What is the response variable in this​ experiment? a The score on the posttest b The score on the pretest c Total in test scores d Difference in test scores

c

To help assess student learning in her music theory ​courses, a music professor at a community college implemented​ pre- and​ post-tests for her music theory students. A​ knowledge-gained score was obtained by taking the difference of the two test scores. What type of experimental design is​ this? a Randomized block design b Completely randomized design c Matched pair. ​d Case-control

d

To help assess student learning in her music theory ​courses, a music professor at a community college implemented​ pre- and​ post-tests for her music theory students. A​ knowledge-gained score was obtained by taking the difference of the two test scores. What is the​ treatment? a Type of school b Background of student c Music theory scores d Music theory course

true

True or False​: In a probability​ model, the sum of the probabilities of all outcomes must equal 1.

true

True or False​: In a probability​ model, the sum of the probabilities of all outcomes must equal 1. Choose the correct answer below. False True

A

True or​ False: When comparing two​ populations, the larger the standard​ deviation, the more dispersion the distribution​ has, provided that the variable of interest from the two populations has the same unit of measure. Choose the correct answer below. A. ​True, because the standard deviation describes how​ far, on​ average, each observation is from the typical value. A larger standard deviation means that observations are more distant from the typical​ value, and​ therefore, more dispersed. B. ​True, because the standard deviation is the difference between the largest and smallest observation. When the standard deviation is​ larger, there is more distance between the largest and smallest​ observation, and​ therefore, more dispersion in the distribution. C. ​False, because the larger the standard deviation​ is, the less dispersion the distribution has. D. ​False, because the standard deviation measures the spread of the​ distribution, not the dispersion of the distribution.

independent

Two events E and F are​ ________ if the occurrence of event E in a probability experiment does not affect the probability of event F.

A

What does it mean if a statistic is​ resistant? Choose the correct answer below. A. Extreme values​ (very large or​ small) relative to the data do not affect its value substantially. B. Extreme values​ (very large or​ small) relative to the data affect its value substantially. C. An estimate of its value is extremely close to its actual value. D. Changing particular data values affects its value substantially.

A

What does it mean if r equals=​0? Choose the correct answer below. A. No linear relationship exists between the variables. B. A relationship does exist between the variables. C. No relationship exists between the variables. D. A linear relationship does exist between the variables.

C

What does it mean to say that the linear correlation coefficient between two variables equals​ 1? What would the scatter diagram look​ like? Choose the correct answer below. A. When the linear correlation coefficient is​ 1, there is a perfect horizontal linear relation between the two variables. The scatter diagram would contain points that all lie on a horizontal line. B. When the linear correlation coefficient is​ 1, there is a perfect negative linear relation between the two variables. The scatter diagram would contain points that all lie on a line with a negative slope. C. When the linear correlation coefficient is​ 1, there is a perfect positive linear relation between the two variables. The scatter diagram would contain points that all lie on a line with a positive slope. D. When the linear correlation coefficient is​ 1, there is no linear relation between the variables. The scatter diagram would contain points that show no discernable relationship.

B

What does it mean when a part of the population is​ under-represented? Choose the correct answer below. A. A part of the population is​ under-represented when their answers on a survey tend not to reflect their true feelings. B. A part of the population is​ under-represented when it is proportionally smaller in a sample than in its population. C. A part of the population is​ under-represented when it is proportionally smaller in its population than in a sample. D. A part of the population is​ under-represented when individuals selected to be in the sample who do not respond to the survey have different opinions from those who do.

c

What does it mean when an observational study is​ prospective? A. A prospective study is a list of all individuals in a population along with certain characteristics of each individual. B. A prospective study requires that individuals look back in time or require the researcher to look at existing records. C. A prospective study collects the data over time.

B

What does it mean when an observational study is​ prospective? A. A prospective study requires that individuals look back in time or require the researcher to look at existing records. B. A prospective study collects the data over time. C. A prospective study is a list of all individuals in a population along with certain characteristics of each individual.

c

What does it mean when an observational study is​ retrospective? A. A retrospective study is a list of all individuals in a population along with certain characteristics of each individual. B. A retrospective study collects the data over time. C. A retrospective study requires that individuals look back in time or require the researcher to look at existing records.

D

What does it mean when sampling is done without​ replacement? Choose the correct answer below. A. Once a sample is​ taken, those individuals are no longer considered part of the population. B. Once an individual is​ selected, the individual can be selected again. C. Once a sample is​ taken, those individuals cannot be selected for any other samples. D. Once an individual is​ selected, the individual cannot be selected again.

a

What is a Pareto​ chart? A. A Pareto chart is a bar graph whose bars are drawn in decreasing order of frequency or relative frequency. B. A Pareto chart is a display of two data sets side by side where the height of each rectangle represents the​ category's frequency or relative frequency. C. A Pareto chart is a combination of a pie chart and a bar graph.

a

What is a bar​ graph? A. A bar graph is a horizontal or vertical representation of the frequency or relative frequency of the categories. The height of each rectangle represents the​ category's frequency or relative frequency. B. A bar graph is a circular graph that uses bars to divide it into segments corresponding to each category. The segments are proportional to the frequency of its category. C. A bar graph represents the frequencies of values either from​ left-to-right or​ right-to-left. The different segments of the bar are used to indicate the different frequencies of each category.

C

What is a closed​ question? What is an open​ question? A. A closed question has many correct​ answers, whereas an open question has only one correct answer. B. A closed question is a​ free-response question, whereas an open question has fixed choices for answers. C. A closed question has fixed choices for​ answers, whereas an open question is a​ free-response question. D. A closed question always has yes or no​ answers, whereas an open question is a​ free-response question.

A

What is a confounding​ variable? A. A confounding variable is an explanatory variable that was considered in a study whose effect cannot be distinguished from a second explanatory variable in the study. B. A confounding variable is the explanatory variable on which a study has been focused. C. A confounding variable is a response variable that was not considered in a study whose effect cannot be distinguished from a second explanatory variable in the study. D. A confounding variable is a response variable that has an effect on the explanatory​ variable, but it cannot be accurately measured in the study.

C

What is a lurking​ variable? A. A lurking variable is a response variable that was not considered in a​ study, but is also affected by the casual relationship of the explanatory variables in the study. In​ addition, lurking variables are typically related to response variables in the study. B. A lurking variable is a quantitative variable that has an infinite number of possible values that are not countable. In​ addition, lurking variables are typically very large numbers that make them​ difficult, if not​ impossible, to include in a study. C. A lurking variable is an explanatory variable that was not considered in a​ study, but that affects the value of the response variable in the study. In​ addition, lurking variables are typically related to explanatory variables in the study. D. A lurking variable is a quantitative variable that has either a finite number of possible values or a countable number of possible values. In​ addition, lurking variables are typically equal to​ zero, or almost equal to zero.

b

What is an​ ogive? Choose the correct answer below. A. A bar graph whose bars are drawn in decreasing order of frequency or relative frequency B. A graph that represents the cumulative frequency or cumulative relative frequency for the class C. A graph that uses​ points, connected by line​ segments, to represent the frequency or relative frequency for each class D. A circle divided into​ sectors, each sector representing a category of data

D

What is a​ case-control study? Choose the correct answer below. A. ​Case-control studies first identify a group of individuals to participate in the study. These individuals are then observed over a period of time. Over this period of​ time, characteristics about the individual are recorded. B. ​Case-control studies are a list of all individuals in a population along with certain characteristics of each individual. C. ​Case-control studies are observational studies that collect information about individuals at a specific point in time or over a very short period of time. D. ​Case-control studies are observational studies that are​ retrospective, meaning that they require individuals to look back in time or require the researcher to look at existing records.

C

What is a​ cross-sectional study? Choose the correct answer below. A. ​Cross-sectional studies first identify a group of individuals to participate in the study. These individuals are then observed over a period of time. Over this period of​ time, characteristics about the individual are recorded. B. ​Cross-sectional studies are observational studies that are​ retrospective, meaning that they require individuals to look back in time or require the researcher to look at existing records. C. ​Cross-sectional studies are observational studies that collect information about individuals at a specific point in time or over a very short period of time. D. ​Cross-sectional studies are a list of all individuals in a population along with certain characteristics of each individual.

A

What is a​ frame? Choose the correct answer below. A. A frame is a list of the individuals in the population being studied. B. A frame is a list of the individuals in the sample being studied. C. A frame is the population being studied. D. A frame is the sample taken from the population being studied.

A

What is a​ residual? What does it mean when a residual is​ positive? Choose the correct answer below. A. A residual is the difference between an observed value of the response variable y and the predicted value of y. If it is​ positive, then the observed value is greater than the predicted value. B. A residual is the difference between an observed value of the response variable y and the value of the corresponding explanatory variable x. If it is​ positive, then the response variable is greater than the explanatory variable. C. A residual is the difference between an observed value of the response variable y and the average value of the response variable. If it is​ positive, then the response variable is greater than the mean. D. A residual is a data point that does not fit the pattern of the rest of the data. If it is​ positive, then the data point should still be included in the data set.

B

What is meant by​ confounding? A. Confounding in a study occurs when a single explanatory variable has a great effect on a response variable. This sometimes causes a misleading interpretation of the relationship between the two variables. B. Confounding in a study occurs when the effects of two or more explanatory variables are not separated.​ Therefore, any relation that may exist between an explanatory variable and the response variable may be due to some other variable or variables not accounted for in the study. C. Confounding in a study occurs when there is little or no actual relationship between the explanatory and response variable other than random chance. This sometimes causes completely unrelated variables to appear to have a causal​ relationship, and can cause variables that have almost no relationship to have a very strong relationship. D. Confounding in a study occurs when the effects of the explanatory variable are​ caused, in some​ part, by the effects of the response variable. When there is zero confounding in a​ study, the effects of the response variable are entirely caused by the effects of the explanatory variable.

D

What is replication in an​ experiment? Choose the correct answer below. A. Replication is randomly assigning each experimental unit to a treatment. B. Replication is grouping together similar experimental units and then using random assignment. C. Replication is pairing up related experimental units. D. Replication is applying each treatment to more than one experimental unit.

B

What is true of the coefficient of​ variation? A. The coefficient of variation is best used when comparing two data sets that use the same units of measure. B. When converting units of​ measure, the coefficient of variation is unchanged. C. The coefficient of variation does not give as accurate a measurement as the standard deviation. D. The coefficient of variation is always more meaningful than the standard deviation.

quantitative variable

What type of variable is required when drawing a​ time-series plot? Why do we draw​ time-series plots? A __________ is required when drawing a​ time-series plot.

B

Which is the superior observational​ study? Why? Choose the correct answer below. A. ​Cross-sectional studies are always the superior observational study because they are cheap and quick to do. B. Neither study is always the superior to the other. Both have advantages and disadvantages that depend on the situation. C. ​Case-control studies are always the superior observational study because they are relatively inexpensive to conduct and can be done relatively quickly.

B

Which sampling method does not require a​ frame? Choose the correct answer below. A. Simple random B. Systematic C. Cluster D. Stratified E. All of the above sampling methods require a frame

A

Why is it important to rotate the two choices presented in the​ question? Which of the following is​ correct? A. The choices need to be rotated to minimize response biases. B. The choices need to be rotated to minimize interviewer error. C. The choices need to be rotated to minimize nonresponses. D. The choices need to be rotated to minimize the effect of a poorly worded question.

case control

_____ ______ studies are retrospective​ studies, meaning that they require individuals to look back in time or require the researcher to look at existing records. In​ case-control studies, individuals who have a certain characteristic may be matched with those who do not.

classes

________ are the categories by which data are grouped.

symmetric

________ if the median and mean are​ equal

inferential

________ statistics uses methods that generalize results obtained from a sample to the population and measure the reliability of the results.

Descriptive

_________ statistics consists of organizing and summarizing information​ collected

completely randomized

__________ ________ design is one in which each experimental unit is randomly assigned to a treatment.

randomized block

__________ _________design is used when the experimental units are divided into homogeneous groups called blocks. Within each​ block, the experimental units are randomly assigned to treatments.

parameter

a _______ is a numerical summary of a population

stratified sample

a ________ is obtained by dividing the population into homogeneous groups and randomly selecting individuals from each group.

proportion

a relative frequency distribution lists the __________ of occurrences of each category of data.

blocking

grouping together similar experimental units and then randomly assigning the experimental units within each group to a treatment is called

matched pairs design

is an experimental design in which the experimental units are paired up. The pairs are matched up so that they are somehow related (that is, the same person before and after a treatment, twins, husband and wife, same geographical location, and so on). There are only two levels of treatment in a matched-pairs design.

right

skewed ______ if the median is less than the mean

B

to estimate the percentage of defects in a recent manufacturing​ batch, a quality control manager at IBM selects every 16th computer that comes off the assembly line starting with the seventh until she obtains a sample of 140 computers A. Convenience B. Systematic C. Simple random D. Cluster E. Stratified

B

​(d) In the​ report, the researchers​ stated, "These results remain significant after adjustment for socioeconomic​ status." What does this​ mean? A. It means that socioeconomic status is an explanatory variable and that including this variable in the study changes the results of the study. B. The researchers made an effort to avoid confounding by accounting for potential lurking variables. C. It means that socioeconomic status is not an explanatory variable and that including this variable in the study does not change the results of the study. D. It means that when the results are separated by socioeconomic​ status, there are significant differences between each socioeconomic status.

statistic

​A(n) ________ is a numerical summary of a sample.

cluster sample

​A_______ is obtained by dividing the population into groups and selecting all individuals from within a random sample of the groups.