Study Guide
In a cumulative relative frequency distribution, the last class will have a cumulative relative frequency equal to: A. None of these alternatives is correct. B. zero. C. one. D. the total number of observations in a data set.
C. one.
The difference between the largest and the smallest data values is the: A. range. B. variance. C. interquartile range. D. coefficient of variation.
A. range.
A numerical value used as a summary measure for a sample, such as sample mean, is known as a: A. sample statistic. B. population parameter. C. population statistic. D. sample parameter.
A. sample statistic.
Statistical studies in which researchers do not control variables of interest are a. observational studies. b. experimental studies. c. invalid studies. d. uncontrolled experimental studies.
a. observational studies.
Data mining is the process of uncovering hidden information that can be used to a. predict. b. justify. c. control. d. explain.
a. predict.
All the data collected for a particular study are referred to as the a. samples. b. elements. c. data set. d. populations.
c. data set.
A manager of a large corporation recommends a $10,000 raise be given to keep a valued subordinate from moving to another company. Consider the internal and external sources of data that might be used to decide whether such a salary increase is appropriate. Classify each of the following sources of data on employee salaries as either internal or external. 1. The Personnel Department - Internal or External 2. The Department of Labor- Internal or External 3. Other industry associations- Internal or External
1. Internal 2. External 3. External
A Bloomberg Businessweek North American subscriber study collected data from a sample of 2861 subscribers. Fifty-nine percent of the respondents indicated an annual income of $75,000 or more, and 50% reported having an American Express credit card. 1. What is the population of interest in this study? a. American Express credit card holders b. Businessweek North American subscribers c. Those with an annual income above $75,000 2. Is annual income a categorical or quantitative variable? a. Categorical b. Quantitative 3. Is ownership of an American Express card a categorical or quantitative variable? a. Categorical b. Quantitative 4. Does this study involve cross-sectional or time series data? a. Cross-sectional b. Time series Determine whether the following two statistical inferences may be made based on the sample data collected. 5. An estimated 59% of the population of subscribers has an annual income of $75,000 or more. a. The data support this inference b. The data do not support this inference 6. An estimated 60% of the population of subscribers has an American Express credit card. a. The data support this inference b. The data do not support this inference
1. b. Businessweek North American subscribers 2. b. Quantitative 3. a. Categorical 4. a. Cross-sectional 5. a. The data support this inference 6. b. The data do not support this inference
A histogram is: A. a graphical presentation of a frequency or relative frequency distribution. B. a graphical method of presenting a cumulative frequency or a cumulative relative frequency distribution. C. the history of data elements. D. the same as a pie chart.
A. a graphical presentation of a frequency or relative frequency distribution.
A company wants to enhance the benefits for its yearly healthcare package offering. It observes the set of employees who smoke on their break times at 10 a.m., 12 p.m., and 2 p.m. It records the number of cigarettes smoked by each individual. This is an example of: A. an observational study. B. a randomized study. C. a controlled experiment. D. an experiment with no placebo.
A. an observational study.
The Department of Homeland Security has noted that on average 1120 suspicious vehicles are stopped and searched each day in the United States. This number is used to estimate the number of cars stopped in an average yearly period. The average number of cars stopped is not an example of: A. descriptive statistics. B. a sample. C. a population. D. statistical inference.
A. descriptive statistics.
The entities on which data are collected are: A. elements. B. observations. C. samples. D. populations.
A. elements.
The entities on which data are collected are: A. elements. B. populations. C. samples. D. observations.
A. elements.
A seven-year medical research study reported that women whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug. 1. This study compared two populations. What were the populations?- a. Women with tissue abnormalities and women without b. Women whose mothers took DES during pregnancy and women whose mothers did not c. Women who developed cancer and mothers who took DES d. Types of DES that cause cancer and types that do not 2. Do you suppose the data were obtained in a survey or in an experiment? a. Survey b. Experiment 3. For the population of women whose mothers took the drug DES during pregnancy, a sample of 3980 women showed that 63 developed tissue abnormalities that might lead to cancer. Provide a descriptive statistic (to 1 decimal) that could be used to estimate the number of women out of 1000 in this population who have tissue abnormalities. _____ out of 1,000 women developed tissue abnormalities 4. For the population of women whose mothers did not take the drug DES during pregnancy, what is the estimate (to 1 decimal) of the number of women out of 1000 who would be expected to have tissue abnormalities? (Hint: remember that women whose mothers took the drug were twice as likely to develop tissue abnormalities.) _____out of 1,000 women developed tissue abnormalities 5. True or false: Medical studies often use a relatively large sample (in this case, 3980) because disease occurrences can be rare and difficult to observe when only isolated populations are considered. a. True b. False
1. b. Women whose mothers took DES during pregnancy and women whose mothers did not 2. a. Survey 3. 15.8 4. 7.9 5. a. True
The correlation coefficient between two scores X and Y equals .80. If both the X scores and the Y scores are converted to z-scores, then the correlation between the z-scores for X and the z-scores for Y would be: A. .80. B. -.20. C. -.80. D. .20.
A. .80.
In a random sample of 200 items, 5 items were defective. An estimate of the percentage of defective items in the population is: A. 2.5%. B. 5.0%. C. 10.0%. D. 20.0%.
A. 2.5%.
Which one of the following statistics measures both the strength and direction of a linear relationship? A. Correlation coefficient B. Regression equation C. Standard deviation D. Covariance
A. Correlation coefficient
Which of the following would likely display a negative relationship when creating a scatter diagram? A. The number of classes a student misses during a semester and the grade obtained in the course B. The amount of time a student spends studying and their plan of going in the course C. The number of miles that a car is driven and the amount of fuel consumed D. The amount of rain that falls in the spring and how quickly the grass grows
A. The number of classes a student misses during a semester and the grade obtained in the course
The owner of a factory regularly requests a graphical summary of all employees' salaries. The graphical summary of salaries is an example of: A.descriptive statistics. B. an experiment. C. statistical inference. D. a sample.
A.descriptive statistics.
The number of observations in a complete data set having 20 elements and 3 variables is: A. 20 + 3 or 23. B. 20. C. 20 - 3 or 17. D. 20*3 or 60.
B. 20.
Which of the following is not resistant to the outliers in a data set? A. Variance B. Mean C. Interquartile range D. Median
B. Mean
A student asked their classmates how tall they are, in which month they were born, and whether they are in a relationship. How many of these variables are quantitative and how many of these variables are categorical? A. Three are quantitative. None is categorical. B. One is quantitative. Two are categorical. C. None is quantitative. Three are categorical. D. Two are quantitative. One is categorical.
B. One is quantitative. Two are categorical.
If the variance of a data set is correctly computed with the formula using n - 1 in the denominator, which of the following is true? A. The data set is too small. B. The data set is a sample. C. The data set is adjusted for skewness. D. The data set is a population.
B. The data set is a sample.
Data obtained from a nominal scale: A. must be alphabetic. B. can be either numeric or nonnumeric. C. must rank and order the data. D. must be numeric.
B. can be either numeric or nonnumeric.
The difference between the lower class limits of adjacent classes provides the: A. number of classes. B. class width. C. class midpoint. D. class limits.
B. class width.
A numerical measure of linear association between two variables is the: A. coefficient of variation. B. covariance. C. variance. D. standard deviation.
B. covariance.
Data collected through a survey attached to this month's pay stub: A. is experimental because the control is the time of month it was administered. B. is considered an observational study because no control is imposed. C. will have no data acquisition error. D. will be useless because not everyone receives the survey.
B. is considered an observational study because no control is imposed.
Some hotels ask their guests to rate the hotel's services as excellent, very good, good, and poor. This is an example of the: A. interval scale. B. ordinal scale. C. nominal scale. D. ratio scale.
B. ordinal scale.
Numerical values that indicate how much or how many are known as A. categorical data. B. quantitative data. C. relative data. D. cumulative data.
B. quantitative data.
Suppose the correlation coefficient rxy between the amount of sleep (in hours) "x" and number of yawns made in 8:00 a.m. classes "y" of 100 business statistics students is computed to be -.82. Then: A. there is a weak positive linear relationship between the two variables. B. the least squares line slopes downward. C. as sleep increases yawns increase as well. D. there is no linear relationship between the two variables.
B. the least squares line slopes downward.
The sum of frequencies for all classes will always equal to: A. 1. B. the number of observations in a data set. C. the number of classes. D. a value between 0 and 1.
B. the number of observations in a data set.
The coefficient of variation is: A. the square of the standard deviation. B. the standard deviation divided by the mean and multiplied by 100. C. the mean divided by the variance multiplied by 100. D. equal to the variance.
B. the standard deviation divided by the mean and multiplied by 100.
Anyone who wants to use the data and statistical analysis as aids to decision making must be aware of the time and cost issues. If important data are not readily available, it would be best to: A. do nothing at all due to cost. B. use a cross-sectional data set. C. conduct a times series analysis. D. borrow another company's data.
B. use a cross-sectional data set.
What is the principal difference between time series data and cross-sectional data? A. Cross-sectional data looks at only a particular "cross-section" of the population. B. Time series data and cross-sectional data are concerned with different sized samples. C. Cross-sectional data are limited to an approximate window of time, while time series data are collected over several time periods. D. Time series data seeks only to capture data within a snapshot in time.
C. Cross-sectional data are limited to an approximate window of time, while time series data are collected over several time periods.
The numerical value of the standard deviation can never be: A. zero. B. an integer. C. negative. D. smaller than the variance.
C. negative.
A sample of 99 distances has a mean of 24 feet and a median of 21.5 feet. Unfortunately, it has just been discovered that an observation that was erroneously recorded as "30" actually had a value of "35." If we make this correction to the data, then: A. we do not know how the median is affected, but the mean increased. B. the mean and median are both increased. C. the median remains the same, but the mean is increased. D. the mean and median remain the same.
C. the median remains the same, but the mean is increased.
The collection of all elements of interest in a particular study is: A. the sample of interest. B. statistical inference. C. the population of interest. D. descriptive statistics.
C. the population of interest.
In a cumulative frequency distribution, the last class will always have a cumulative frequency equal to: A. 100. B. the total number of classes in a data set. C. the total number of observations in a data set. D. one.
C. the total number of observations in a data set.
A time series is a sequence of data points, typically consisting of successive measurements made over a time interval. Examples of the time series include all except: A. Ocean tides. B. a stock's opening price for each month. C. the volume of shares traded today in the stock market. D. point differential against opponents for a football team this year.
C. the volume of shares traded today in the stock market.
A student made scores of 85, 56, and 91 on her first three statistics tests. What score does she need to make on her next test to have an 80 test average? A. 77 B. 78 C. 87 D. 88
D. 88
Which of the following is not a type of data acquisition errors? A. The person asking a survey question may place undo emphasis on one of the answer choices. B. A subject's answers may be transcribed incorrectly. C. Data being used before the source is properly vetted. D. A particularly extreme value is verified, and is still included in the data set.
D. A particularly extreme value is verified, and is still included in the data set.
The American Statistical Association describes eight general topic areas and specifies important ethical considerations under each topic. One area is "Professionalism". Professionalism points out the need for competence, judgment, diligence, self-respect, and worthiness of the respect of other people. Which of the following adheres to upholding the ethical guidelines for statistical practice? A. Use only statistical methodologies suitable to the data and to obtaining valid results. For example, address the multiple potentially confounding factors in observational studies and use due caution in drawing causal inferences. B. Guard against the possibility that a predisposition (bias) by investigators or data providers might predetermine the analytic result. C. Account for all data considered in a study and explain the sample(s) actually used. D. All of these are valid elements of professionalism, and are maintaining ethical guidelines.
D. All of these are valid elements of professionalism, and are maintaining ethical guidelines.
Which of the following provides a measure of central location for the data? A. Mode B. Variance C. Standard deviation D. Mean
D. Mean
When a set of data has suspect outliers, which of the following is the referred measure of central tendency? A. Mean B. Range C. Standard deviation D. Median
D. Median
The reversal of conclusions based on aggregate and unaggregated data is called: A. cause and effect. B. correlation. C. crosstabulation relationships. D. Simpson's paradox.
D. Simpson's paradox.
Which of the following graphical displays should not be used for quantitative data? A. Dot Plot B. Histogram C. Scatter Diagram D. Stacked Bar Chart
D. Stacked Bar Chart
Positive values of covariance indicate: A. a positive variance of the x values. B. a positive variance of the y values. C. that the standard deviation is positive. D. a positive relation between the independent and the dependent variables
D. a positive relation between the independent and the dependent variables
The major applications of data mining have been made by companies with a strong _____ focus. A. human resource B. research and development C. electronic design D. consumer
D. consumer
When data are positively skewed, the mean will usually be: A. equal to the median. B. smaller than the median. C. a negative integer. D. greater than the median.
D. greater than the median.
The pth percentile is a value such that at least p percent of the observations are: A. less than this value. B. greater than this value. C. greater than or equal to this value. D. less than or equal to this value.
D. less than or equal to this value.
A frequency distribution is a tabular summary of data showing the: A. fraction of items in several classes. B. percentage of items in several classes. C. relative percentage of items in several classes. D. number of items in several classes.
D. number of items in several classes.
In data mining, statistical models play an important role in developing _____. A. human resources B. financial organizations C. businesses D. predictive models
D. predictive models
A graphical presentation of the relationship between two quantitative variables is called a: A. dot plot. B. histogram. C. stem-and-leaf display. D. scatter diagram.
D. scatter diagram.
A graphical display for depicting multiple bar charts on the same display is called a: A. scatter diagram. B. histogram. C. stacked bar chart. D. side-by-side bar chart.
D. side-by-side bar chart.
A display used to compare the frequency, relative frequency, or percent frequency of two categorical variables is a: A. scatter diagram. B. stem-and-leaf display. C. pie chart. D. stacked bar chart.
D. stacked bar chart.
Which of the following is least useful in making comparisons or showing the relationships of two variables? A. stacked bar chart B. scatter diagram C. crosstabulation D. stem-and-leaf display
D. stem-and-leaf display
All of the following are examples of observational studies except: A. a Gallup poll measuring the approval rating of the President. B. an online survey to record your satisfaction with a company's service. C. the number of cars running a stop sign in a residential area during rush hour. D. the behavior of Walmart shoppers after they are given a $20 gift card from the store.
D. the behavior of Walmart shoppers after they are given a $20 gift card from the store.
In data mining, one of the common statistical approaches to evaluating a predictive model's reliability is to divide the sample data set into two parts: a. A training data set and a test data set. b. A categorical data set and a quantitative data set. c. A discrete data set and a continuous data set. d. A past data set and a future data set.
a. A training data set and a test data set.
Which of the following is an example of an observational study? a. All of these choices are examples of observational studies. b. Customer response to quality of service at a retail store is recorded for 200 customers. c. Students are asked what their favorite subject is in school. d. The temperature is measured each day for 30 days.
a. All of these choices are examples of observational studies.
If a negative relationship exists between two variables, x and y, which of the following statements is true? a. As x increases y decreases. b. As x decreases y decreases. c. As x increases y increases. d. As x decreases y stays the same.
a. As x increases y decreases.
The Kroger Company is one of the largest grocery retailers in the United States, with over 2000 grocery stores across the country. Kroger uses an online customer opinion questionnaire to obtain performance data about its products and services and learn about what motivates its customers (Kroger website, April 2012). In the survey, Kroger customers were asked if they would be willing to pay more for products that had each of the following four characteristics. The four questions were: Would you pay more for: products that have a brand name? products that are environmentally friendly? products that are organic? products that have been recommended by others? For each question, the customers had the option of responding "yes" if they would pay more or "no" if they would not pay more. a. Is the data collected by Kroger in this example categorical or quantitative? Categorical Quantitative b. What measurement scale is used? Ratio Interval Nominal Ordinal
a. Categorical b. Nominal
Figure 1.11 provides a bar chart showing the amount of federal spending in trillions of inflation adjusted dollars (2012) for the years 2004 to 2012 (The Heritage Foundation website, June 13, 2013). a. What is the variable of interest? Earnings for Federal spending Federal spending measured in millions of dollars Federal spending measured in trillions of dollars b. Are the data categorical or quantitative? Categorical Quantitative c. Are the data time series or cross-sectional? Cross-sectional Time series
a. Federal spending measured in trillions of dollars b. Quantitative c. Time series
How is an outlier represented on a boxplot? a. It is represented by the "*" symbol. b. It is represented by the length of the box. c. It is represented by the middle line in the box. d. It is represented by the whiskers.
a. It is represented by the "*" symbol.
Which of the following represents the data point that occurs most frequently in a set of observations? a. Mode b. All of these choices are correct. c. Median d. Mean
a. Mode
Which of the following describes a population? a. The complete collection of individuals or objects that are of interest. b. A planned activity whose results yield a set of data. c. A sample of the individuals or objects that are of interest. d. A characteristic of an individual element.
a. The complete collection of individuals or objects that are of interest.
In an experiment, the investigator modifies the environment and controls the process being observed. a. True b. False
a. True
Which of the following variables is quantitative? a. Weight of a package b. Phone number c. Zip code d. All of these choices are correct.
a. Weight of a package
Thirty-two percent of college students at a university plan to attend graduate school, 18% plan to work for a year before attending graduate school, 25% plan to begin their career upon graduation and 25% are undecided. The graphical device(s) that can be used to present these data is (are): a. both a bar graph and a pie chart. b. a line graph. c. only a bar graph. d. only a pie chart.
a. both a bar graph and a pie chart.
The 50th percentile is the a. median. b. mode. c. variance. d. mean.
a. median.
Which of the following statements is not a descriptive statistic? a. 75% of a state's residents approve of the governor's job performance. b. 15 school age children were surveyed for their favorite subject. c. The average weight of 50 dogs of the same breed was 54 pounds. d. The average age of students attending a university was 21.
b. 15 school age children were surveyed for their favorite subject.
If the sample standard deviation for the weight of a sample of ten boxes is 45.6 pounds, what is the variance for this set of data? a. 14.42 b. 2079.36 c. 6.75 d. 45.6
b. 2079.36
The number of personal days taken (per month) by 300 employees at a large corporation is summarized below. The class width for this distribution is # DAYS FREQ 0-3 210 4-7 50 8-11 30 12-15 10 a. 5 b. 4 c. 15 d. 3
b. 4
Descriptive statistics can be a. numerical. b. Any of these choices would be correct. c. tabular. d. graphical.
b. Any of these choices would be correct.
A statistical procedure is not the same as its implementation in Excel. a. True b. False
b. False
Each row in a worksheet corresponds to a variable and each column corresponds to an observation. a. True b. False
b. False
In a percent frequency distribution, the last class will have a percent frequency equal to: a. 1 b. It depends on the data. c. 100 d. 0
b. It depends on the data.
A survey of 40 students at an elementary school found that the average number of tardy days per semester was 15. The 15 is an example of a. qualitative data. b. both choices "quantitative data" and "a descriptive statistic" are correct. c. a descriptive statistic. d. quantitative data.
b. both choices "quantitative data" and "a descriptive statistic" are correct.
The correlation coefficient: a. can be larger than 1. b. can be negative. c. cannot be less than zero. d. is the same as the covariance.
b. can be negative.
Statistical studies in which researchers control variables of interest are a. non experimental studies. b. experimental studies. c. observational studies. d. controlled observational studies.
b. experimental studies.
A tabular summary of a set of data showing the total number of items in several nonoverlapping classes is a: a. frequency. b. frequency distribution. c. relative frequency distribution. d. cumulative frequency distribution.
b. frequency distribution.
To date, the major applications of data mining have been implemented by companies with a strong a. manufacturing focus. b. technology focus. c. consumer focus. d. environmental focus.
c. consumer focus.
Statistical inference a. is the same as descriptive statistics. b. is the process of drawing inferences about the population based on the information taken from the sample. c. is the same as a census. d. refers to the process of drawing inferences about the sample based on the characteristics of the population.
b. is the process of drawing inferences about the population based on the information taken from the sample.
A researcher is gathering data regarding four manufacturers of automobiles designated as follows: Dodge = 1; Toyota = 2; Honda = 3; Ford = 4. The designated brands represent: a. both quantitative or qualitative data. b. qualitative data. c. label data. d. quantitative data.
b. qualitative data.
Consider the following data set.Which of the following is the leaf unit if you were to construct a stem-and-leaf display? 10 19 3 9 25 22 15 11 8 22 a. 10 b. 0.1 c. 1 d. 20
c. 1
In a sample of size n , the sum of the percent frequencies is always: a. n b. 100 × relative frequency c. 100 d. 1
c. 100
The median of a data set is represented by the: a. 100th percentile. b. 25th percentile. c. 50th percentile. d. 75th percentile.
c. 50th percentile.
Which of the following attributes is qualitative? a. The number of movies seen by an individual in one year b. The square footage of a house c. A person's favorite food d. The number of boys in a class
c. A person's favorite food
What does the vertical axis on a histogram represent? a. It represents the class limits. b. It represents the variable of interest. c. It represents the frequency, percent frequency or relative frequency. d. There is no vertical axis on a histogram.
c. It represents the frequency, percent frequency or relative frequency.
Which of the following describes a variable measured on an ordinal scale? a. Arithmetic operations are meaningful b. The ratio of two values is meaningful c. Order can be assigned to the categories d. It is a quantitative variable
c. Order can be assigned to the categories
Which scale of measurement can be used with quantitative data? a. Any of these choices can be used for quantitative data. b. Ordinal c. Ratio d. Nominal
c. Ratio
Which of the following can be used to graphically present quantitative data? a. Bar graph b. Pie chart c. Stem-and-leaf display d. Both choices "Bar graph" and "Pie chart" are correct.
c. Stem-and-leaf display
What types of variables can be displayed by a scatter diagram? a. One quantitative and one qualitative variable b. Only two discrete quantitative variables c. Two quantitative variables d. Two qualitative variables
c. Two quantitative variables
In a sample of 200 people who own a house, 180, or 90%, also own two or more vehicles. The 90% is an example of a. a sample. b. a population. c. a descriptive statistic. d. statistical inference.
c. a descriptive statistic.
In order to determine whether a restaurant should offer service on Sunday the manager asked 50 regular customers if they would dine at the restaurant on Sundays. She found that 30, or 60%, would like the restaurant to open on Sundays. The 50 customers are an example of a. a population. b. a mean. c. a sample. d. statistical inference.
c. a sample.
A relative frequency distribution is: a. a graphical form of representing data. b. a graphical device for presenting qualitative data. c. a tabular summary of a set of data showing the fraction of items in each of several non overlapping classes. d. a tabular summary of a set of data showing the number of items in each of several non overlapping classes.
c. a tabular summary of a set of data showing the fraction of items in each of several non overlapping classes.
The sum of deviations of the individual data elements from their mean is a. sometimes greater than and sometimes less than zero, depending on the data elements. b. always greater than zero. c. always equal to zero. d. always less than zero.
c. always equal to zero.
Data warehousing refers to all of the following activities except a. storing data. b. maintaining data. c. analyzing data. d. capturing data.
c. analyzing data.
The Department of Transportation of a city has noted that on the average there are 17 accidents per day. The average number of accidents is an example of a. statistical inference. b. a population. c. descriptive statistic. d. a sample.
c. descriptive statistic.
The relative frequency of a class: a. is always equal to 1%. b. is equal to the frequency of the class multiplied by 100%. c. is equal to the frequency of the class divided by the total number of observations, n. d. is equal to the frequency of the class.
c. is equal to the frequency of the class divided by the total number of observations, n.
If a data set has an odd number of observations, the median a. Cannot be determined. b. is the average value of the two middle items when all items are arranged in ascending order. c. is the value of the middle item when all items are arranged in ascending order. d. must be equal to the mean.
c. is the value of the middle item when all items are arranged in ascending order.
A linear relationship is a pattern in which a. the scatter diagram shows a curved pattern. b. the scatter diagram shows an irregular rate of decrease or an irregular rate of increase. c. the scatter diagram shows a constant rate of increase or a constant rate of decrease. d. the scatter diagram shows a random pattern of data points.
c. the scatter diagram shows a constant rate of increase or a constant rate of decrease.
What is the range of income for five randomly chosen individuals aged 22 to 24? The data are $72,500, $26,200, $17,900, $36,000, $52,100. a. 0 b. $40,940 c. $20,400 d. $54,600
d. $54,600
The correlation coefficient ranges between a. 0 and 1 b. minus infinity and plus infinity c. 1 and 100 d. -1 and +1
d. -1 and +1
In a cumulative relative frequency distribution, the last class will have a cumulative relative frequency equal to: a. 0 b. 100 c. the total number of elements in the data set. d. 1
d. 1
Which of the following statements is true with respect to bar charts? a. The width of the bars depends on the number of observations in the category. b. A bar chart is used only with quantitative data sets. c. A circle is drawn to represent the entire data set. d. A bar chart can be used for a data set with a relatively small number of possible categories.
d. A bar chart can be used for a data set with a relatively small number of possible categories.
Which of the following is a measure of location? a. Mean b. Mode c. Median d. All of the choices are correct.
d. All of the choices are correct.
Which of the following statements is correct when computing descriptive statistics from grouped data? a. The mean, variance and standard deviations are approximations. b. Data values are treated as if they occur at the midpoint of a class. c. The grouped data result is less accurate than the ungrouped result. d. All of the choices are correct.
d. All of the choices are correct.
In a five-number summary, which of the following is used for data summarization? a. the first quartile b. the third quartile c. the median d. All of the choices are used in a five-number summary.
d. All of the choices are used in a five-number summary.
Which of the following should be considered when acquiring data for a study? a. Time to collect data b. Cost to collect data c. The possibility of data acquisition errors d. All of these choices
d. All of these choices
Where can you find descriptive statistics being reported? a. In financial reports b. On the television c. In company reports d. All of these choices are correct.
d. All of these choices are correct.
Which of the following is a descriptive statistic? a. A histogram b. A bar chart c. An average d. All of these choices are correct.
d. All of these choices are correct.
Which of the following is a possible reason for an outlier in a data set? a. The individual in question belongs to a different group than the bulk of individuals measured. b. A mistake was made while taking a measurement or entering it into the computer. c. The outlier is a legitimate data value and represents natural variability for the group and variables measured. d. All of these choices are possible reasons for an outlier.
d. All of these choices are possible reasons for an outlier.
Which of the following is an example of data typically available from internal company records? a. Federal Reserve Board b. Census Bureau c. Department of Commerce d. Credit records
d. Credit records
A grocery store manager recorded the purchase amount of a sample of 75 customers who purchased groceries at their store. What data are being collected in this study? a. The type of merchandise they bought b. The number of customers who enter the store c. The age of the customer d. How much money they spent
d. How much money they spent
Which of the following variables is qualitative? a. Weight b. Height of a person c. Miles driven per year d. Telephone number
d. Telephone number
The following is a summary of the number of hours spent per work day involved in meetings for a sample of 50 people. What is wrong with the relative frequency distribution? Hours/Day - Relative Frequency 0-1 - .45 2-4 - .30 5-7 - .10 a. The classes overlap. b. There should be seven classes not three. c. There is nothing wrong with the frequency distribution. d. The relative frequencies do not add to 1.
d. The relative frequencies do not add to 1.
A student counted the number of people who crossed an intersection in a one-hour period. She found that 23 people crossed the road during the one-hour period. She is interested in the number of people who would typically cross this intersection in a 12-hour day. Which of the following statements is true? a. The sample consists of all the people who cross the road in a 12-hour day. b. The population consists of the 23 people who crossed the road in the 12-hour period. c. The population is the 12-hour day. d. The sample consists of the 23 people who were observed crossing the road in the one-hour period.
d. The sample consists of the 23 people who were observed crossing the road in the one-hour period.
Suppose the average number of items per purchase at a retail store is 5 and the average number of items per purchase at a different but similar retail store is also 5. Which of the following is true? a. Their medians must also be equal. b. Their standard deviations must also be equal. c. Their variances must equal zero. d. There are no other conclusions that can be made about their descriptive statistics.
d. There are no other conclusions that can be made about their descriptive statistics.
