Statistics Exam 1 Study Guide
The sum of relative frequencies for each interval is ______. a. 100% b. both A and B c. 1.00 d. equal to the total number of scores in a distribution
c. 1.00
A researcher records the following scores: 5, 3, 7, 6, 2, 8, 0, and 1. In terms of these data, the sum of the squared differences of scores from their mean is ______. a. 164 b. 60 c. 0 d. 8
b. 60
Which of the following best describes a dependent variable? a. the manipulated variable b. the measured behavior c. the sample variable d. the population variable
b. the measured behavior
What is the corresponding percentile of a percentile point? a. the score b. the percentile rank c. the frequency d. always 100%
b. the percentile rank
A researcher identifies college students as a group of interest to test her hypothesis. She then identifies a few local college students and selects a small group of the local college students to be observed. In this example, the sample is ______. a. not clearly identified b.the small group of college students who here observed c. all college students d. the few local college students
b. the small group of college students who here observed
All other things being equal (so assuming that the value of SS never changes), as sample size increases, ______. a. the value in the numerator for sample variance increases b. the value of sample variance decreases c. the degrees of freedom for sample variance decrease d. the value in the denominator for sample variance decreases
b. the value of sample variance decreases
A relative frequency distribution is appropriate when ______. a. there are open classes b. there are large frequency counts in each interval c. the data are grouped into relatively small intervals d. the interval width is too large
b. there are large frequency counts in each interval
The population mean is symbolized as ______, whereas the sample mean is symbolized as ______. a. M; b. u; M c. N; n d. n; N
b. u; M
Each deviation in the numerator for variance is squared because ______. a. this inflates the value for variance, making it more accurate b. without squaring each deviation, the solution for SS would be zero c. both A and C d. without squaring each deviation, the solution could be negative
b. without squaring each deviation, the solution for SS would be zero
A percentile point is ______. a. the range of values contained in each interval of a grouped frequency distribution b.the value of a score on a measurement scale below which a specified percentage of scores in a distribution fall c. an interval with no defined upper or lower boundary d. a summary display that distributes the sum of percentages across a series of intervals
b.the value of a score on a measurement scale below which a specified percentage of scores in a distribution fall
A simple frequency distribution ______. a. can be used to summarize grouped data b. can be used to summarize ungrouped data c. summarizes the frequency of scores in a given category or range d. all of these
d. all of these
Grouped data are distributed into ______, whereas ungrouped data are distributed into ________. a. intervals; statistics b. categories; intervals c. statistics; intervals d. intervals; categories
d. intervals; categories
The distribution of annual household income in the United States is positively skewed. If the median annual income is about $56,000, this implies that the mean annual household income in the United States is ______. a. smaller b. There is not enough information to answer this question. c. the same d. larger
d. larger
A percentile is also called a ______. a. distribution b. range c. score d. percentile point
d. percentile point
______ is the variable that is believed to change in the presence of the independent variable. a. Dependent variable b. Quasi-independent variable c. Independent variable
a. Dependent variable
A researcher measures the time (in seconds) that it takes children to complete a basic reading skills task. What type of graphical display would be most appropriate for summarizing the frequency of children falling into different intervals of time? a. histogram b. bar chart c. scatter gram d. all of these
a. histogram
The mode can be used with the mean to describe which of the following variables? a. rankings b. gender c. the winning percentage of teams in a league d. all of these
c. the winning percentage of teams in a league
A cumulative percentage summary that indicates the percentage of scores at or below a given value is called a ______. a. relative frequency b. relative percentage c. cumulative frequency d. percentile rank
d. percentile rank
A characteristic (usually numeric) that describes a sample is called a ______. a. population parameter b. sample c. population d. sample statistic
d. sample statistic
Which of the following distributions has the largest variability? a. scores: 2, 3, 4, 5, and 6 b. scores: 1, 2, 3, 4, and 5 c. scores: 22, 24, 26, 28, and 30 d. scores: 1, 3, 6, 9, and 12
d. scores: 1, 3, 6, 9, and 12
Which of the following describes a descriptive statistic? a. predict b. summarize c. infer d. generalize
b. summarize
State the problem with this simple frequency distribution. a. The class intervals overlap. b. The interval width is unequal. c. The interval width is too small. d. The number of intervals is too small.
a. The class intervals overlap.
What is the percentile point at the 90th percentile in the following distribution? a. 10 b. 9 c. 9.5 d. 10.5
a. 10
A researcher decides to split scores on an exam into quartiles. She determines that a score of 64 is at the 25th percentile, a score of 74 is at the 50th percentile, and a score of 80 is at the 75th percentile. What is the interquartile range (IQR) for these data? a. 16 b. There is not enough information to answer this question. c. 10 d. 6
a. 16
A researcher finds that 12% of participants make between three and five visits to a physician each year. What are the real limits for this interval? a. 2.5-5.5 b. 2.5-3.5 c. 3-5 d. equal to the sum of the products for the previous interval
a. 2.5-5.5
A researcher finds that 12 persons in a sample of 60 reported getting between 4 and 6 hr of sleep per night. What is the relative percentage for this interval? a. 20% b. 24% c. There is not enough information to answer this question. d. 22%
a. 20%
A researcher computes the definitional formula for SS, as finds that E(x-M)2= 44. If this is a sample of 12 scores, then what would the value of sample variance be using the definitional formula? a. 4.0 b. not possible to know because the scores are not given c. 3.7 d. 44
a. 4.0
Fill in the missing values for A and B in this frequency distribution table: a. A = 3.2, B = 13 b. A = 3.1, B = 14 c. A = 3.3, B = 13 d. There is not enough information to complete this table.
a. A = 3.2, B = 13
A researcher records the following scores on a working memory quiz for two samples. Which sample has the largest standard deviation? Sample A: 2, 3, 4, 5, 6, 7, and 8 Sample B: 4, 5, 6, 7, 8, 9, and 10 a. Both samples have the same standard deviation. b. Sample A c. Sample B
a. Both samples have the same standard deviation.
______ are measured in whole units or categories that are not distributed along a continuum. a. Discrete data b. Open-ended data c. Continuous data d. Quantitative data
a. Discrete data
A researcher measures the mean time (in seconds) it takes two groups of children to complete an activity task. She finds that Group A (M = 22 s) completed the task more quickly than Group B (M = 36 s). She then computes a weighted mean for both groups combined and calculates = 26. Based on the information provided, which group had a larger sample size? a. Group A b. It is not possible to know this without knowing the sample size for each group. c. Group B d. The sample size is equal in both groups.
a. Group A
A researcher measures the amount of coffee consumed by college students while studying during the final exam week. In her study, she found that students drink 2.3 ± 0.8 (M ± SD) cups of coffee per study session. Assuming the data are normally distributed, which of the following is the most appropriate conclusion? a. Most students drink between 1.5 and 3.1 cups of coffee per study session. b. Most students drink between 0.7 and 2.3 cups of coffee per study session. c. Most students drink between 2.3 and 3.9 cups of coffee per study session. d. The average student drinks less than 2.3 cups of coffee per study session.
a. Most students drink between 1.5 and 3.1 cups of coffee per study session.
Which of the following is a property of the standard deviation? a. Multiplying each score by the same constant will change the standard deviation by that constant. b. Adding the same constant to each score will change the standard deviation by that constant. c. The standard deviation varies between - and +. d. both B and C
a. Multiplying each score by the same constant will change the standard deviation by that constant.
The size of a population is symbolized as ______, whereas the size of a sample is symbolized as ______. a. N; n b. ; M c. n; N d. M;
a. N; n
A researcher records a sample of 30 exam scores and finds that if these data were treated as a population, that the population variance calculation for these data is larger than the sample variance calculation for these same data. Is this outcome for variance possible? a. No, the sample variance will be larger because SS is divided by degrees of freedom in the denominator of the variance formula. b. No, the population variance will only be larger when at least 50 scores are recorded. c. Not possible to know because the scores are not given. d. Yes, the population variance is usually larger than the sample variance.
a. No, the sample variance will be larger because SS is divided by degrees of freedom in the denominator of the variance formula.
A researcher records the following scores for attention during a video game task for two samples. Which sample has the largest standard deviation? Sample A: 10, 12, 14, 16, and 18 Sample B: 20, 24, 28, 32, and 36 a. Sample B b. Both samples have the same standard deviation. c. Sample A
a. Sample B
A researcher reports that "the average shopper in the sample (n = 12) purchased $65.00 worth of items ( = $65.00) during a busy shopping day." What mistake was made is this citation? a. The sample mean is written using the wrong notation. b. The sample size is written using the wrong notation. c. None; this citation is written appropriately. d. both B and C
a. The sample mean is written using the wrong notation.
A professor grades 120 research papers and reports that the average score was an 80%. What do we know about the sum of the differences of these 120 scores from their mean of 80%? a. The sum of the differences is equal to zero. b. The sum of the differences is 80%, the same as the mean. c. It is impossible to know without knowing each of the 120 scores. d. The sum of the differences is minimal.
a. The sum of the differences is equal to zero.
A researcher wants to determine how many participants will take less than 24 s to complete a cognitive performance task. If he constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer his question? a. a cumulative frequency distribution from the bottom up b. a cumulative frequency distribution from the top down c. a simple frequency distribution d. a relative frequency distribution
a. a cumulative frequency distribution from the bottom up
Which of the following is a type of graphical display used to summarize qualitative, discrete data? a. both A and B b. histogram c. pie chart d. bar chart
a. both A and B
Multiplying or dividing each score in a distribution by the same constant will ______. a. cause the mean to change by that constant b. not change the mean at all because each score was multiplied or divided by the same constant
a. cause the mean to change by that constant
Grouped data are to ungrouped data as ______. a. continuous is to discrete b. descriptive is to inferential c. inferential is to descriptive d. qualitative is to quantitative
a. continuous is to discrete
Based on the following graphical summary display, what research design was used to record and analyze these data? a. correlational b. experimental c. either B or C d. quasi-experimental
a. correlational
The use of tables and graphs to summarize data is an example of ______. a. descriptive statistics b. generalization c. interpretation d. inferential statistics
a. descriptive statistics
A researcher selects a sample of 24 participants and has them complete a survey on dating preferences. In this example, what are the degrees of freedom for sample variance and what does this represent? a. df = 23; it represents the number of scores that are free to vary in a sample. b. df = 23; dividing SS by df makes the sample variance a biased estimator of the population variance. c. df = 24; dividing SS by df makes the sample variance an unbiased estimator of the population variance. d. df = 24; it represents the number of scores that are free to vary in a sample.
a. df = 23; it represents the number of scores that are free to vary in a sample.
The definitional formula ______ the computational formula for SS. a. equals b. diminishes c. explains d. estimates
a. equals
A researcher tests whether the dosage level of some drug (low, high) causes significant differences in health. To do this, the researcher randomly assigns rat subjects to receive a low or high dosage of the drug and records health-related measures in both groups. The type of method described is ______. a. experimental b. quasi-experimental c. correlation d. operational
a. experimental
A researcher summarizes a set of frequency data into five intervals. This is an example of a frequency distribution for ______. a. grouped data b. ungrouped data c. population parameters d. inferential statistics
a. grouped data
A researcher measures the weight (in ounces) of newborn infants in the month of March. What type of graphical display would be most appropriate for summarizing the frequency of infants falling into different intervals of weight? a. histogram b. bar chart c. scatter gram d. all of these
a. histogram
A researcher records the time (in seconds) that participants arrive late for a scheduled research study. Assuming these data are normally distributed, which measure of central tendency is most appropriate to describe these data? a. mean b. median c. mode d. None; it is inappropriate to describe the central tendency of these data.
a. mean
An education counselor records the number of high school graduates enrolled in community colleges, 4-year colleges, and universities. What scale of measurement is the type of college? a. nominal b. interval c. ordinal d. ratio
a. nominal
A movie critic rates a movie on a scale from 1 (lowest) to 4 (highest) stars. What scale of measurement are the ratings? a. ordinal b. ratio c. interval d. nominal
a. ordinal
A psychologist reviews her notes for all her patients and determines that on average her patients complete therapy in 24 days. The average time to complete therapy among all her patients is called a(n) ______. a. population parameter b. inferential statistic c. sample statistic d. time trial
a. population parameter
Recording whom students study with describes ______ types of data; whereas recording the number of hours spent studying per week describes ______ types of data. a. qualitative; quantitative b. continuous; discrete c. discrete; continuous d. quantitative; qualitative
a. qualitative; quantitative
A researcher compares the amount of college debt (in dollars) that undergraduate students incur up to their 4-year degree. College debt is on what scale of measurement? a. ratio b. interval c. nominal d. ordinal
a. ratio
If a portion of people from a population are asked to complete an assessment, then the average score among that group of people would be considered a ______. a. sample mean b. population mean c. median split d. modal mean
a. sample mean
Which type of mean is used to describe a portion of individuals in a given population? a. sample mean b. population mean c. restricted mean d. none of these
a. sample mean
Which of the following can be used to estimate the median? a. the 50th percentile of a cumulative percentage distribution b. the 50th percentile of a relative percentage distribution c. the mode d. the mean
a. the 50th percentile of a cumulative percentage distribution
Bar charts are a lot like histograms, except ______. a. the bars displayed in the graph do not touch b. the bar chart summarizes quantitative data c. the bar chart summarizes continuous data d. all of these
a. the bars displayed in the graph do not touch
Which of the following measures of attraction is an example of a ratio scale measurement? a. the physical proximity (in feet and inches) between two romantic partners b. a rating of attraction from most attractive to least attractive c. a 6-point rating scale from 1 (attractive) to 6 (unattractive) d. the status of the relationship (acquaintance, dating, married)
a. the physical proximity (in feet and inches) between two romantic partners
An interquartile range removes ______. a. the top and bottom 25% of scores in a distribution before calculating range b. scores above only the 75th percentile before calculating range c. scores below only the 25th percentile before calculating range d. all of these
a. the top and bottom 25% of scores in a distribution before calculating range
Regardless of the number of scores in a distribution, the range only includes ______ score(s) in its calculation. a. two b. at most two c. the average d. one
a. two
The following frequency distribution is an example of a. ungrouped data b. categorical data c. grouped data d. both B and C
a. ungrouped data
What is the percentile point at the 50th percentile for the following distribution? a. 21 b. 25 c. 23.5 d. 25.5
b. 25
As a general rule, a simple frequency distribution should have between ______. a. 8 and 12 intervals b. 5 and 20 intervals c. 5 and 10 intervals d. 3 and 6 intervals
b. 5 and 20 intervals
A researcher records the following scores for an Olympic gymnast following her routine: 9.9, 9.8, 9.6, 9.5, 9.7, 9.1, 8.9, and 9.8. What is the range for the scores? a. It is not possible to compute a range with an even number of scores. b. 1.0 (9.9 to 8.9) c. 0.3 (9.8 to 9.5) d. 0.5 (9.6 to 9.1)
b. 1.0 (9.9 to 8.9)
A researcher computes the computational formula for SS, as finds that Ex= 39 and Ex2= 271. If this is a sample of six scores, then what would SS equal using the computational formula? a. 3.5 b. 17.5 c. not possible to know because the sample mean is not given d. 232
b. 17.5
The following is a simple frequency distribution table. If we convert this frequency distribution to relative percentages, which of the following gives the corresponding relative percentages in each interval listed from the top down? a. 0.2, 0.13, 0.17, 0.33, 0.17 b. 20%, 13%, 17%, 33%, 17% c. 6, 10, 15, 25, 30 d. 20%, 33%, 50%, 67%, 100%
b. 20%, 13%, 17%, 33%, 17%
A researcher records the time in seconds it takes a sample of participants to walk alone through a dark portion of campus. The researcher computes SS = 1,200. Assuming that a sample of 25 participants was observed in this study, what is the standard deviation for these data? a. 6.9 s b. 7.1 s c. 48 s d. 50 s
b. 7.1 s
What is the percentile point at the 80th percentile in the following distribution? a. 7 b. 8 c. 6 d. 2
b. 8
State the type of graphical display for Graph A and Graph B. a. A is a bar chart; B is a histogram. b. B is a bar chart; A is a histogram. c. Both graphs are histograms. d. Both graphs are bar charts.
b. B is a bar chart; A is a histogram.
A researcher records the following data: 4, 4, 4, 4, and 3. How would you describe the variability of these data? a. It is equal to zero because scores are approximately the same. b. It is very small (close to 0) because scores are approximately the same. c. It is very large (much greater than 0) because 3 is an outlier in the data. d. It is negative because 3 is less than the other scores in the distribution.
b. It is very small (close to 0) because scores are approximately the same.
A researcher records the following data for the number of complaints filed (per day) following a controversial policy change at a local business: 3, 8, 5, 0, 4, 6, 2, 1, 1, 4, 2, and 0. Is the mean equal to the median in this example? a. Yes. b. No; the mean is larger than the median. c. There is not enough information to answer this question. d. No; the median is larger than the mean.
b. No; the mean is larger than the median.
A researcher records the following data for the number of times an interviewer is interrupted during a series of interviews: 0, 0, 3, 2, 5, 3, 0, 8, 0, 2, 1, and 1. Is the mode equal to the median in this example? a. Yes. b. No; the median is larger than the mode. c. No; the mode is larger than the median. d. There is not enough information to answer this question.
b. No; the median is larger than the mode.
A researcher records the following data for the time (in seconds) it takes five rats to cross an electrical grid to obtain reinforcement on the other side: 12, 9, 13, 4, and 12. Is the mean equal to the mode in this example? a. There is not enough information to answer this question. b. No; the mode is larger than the mean. c. Yes. d. No; the mean is larger than the mode.
b. No; the mode is larger than the mean.
To measure attraction, a researcher records the following data for the distance (in inches) between two persons sitting in a waiting room: 46, 32, 10, 23, 18, 46, and 60. Is the mode equal to the median in this example? a. Yes. b. No; the mode is larger than the median. c. There is not enough information to answer this question. d. No; the median is larger than the mode.
b. No; the mode is larger than the median.
A researcher distributes frequencies into the following intervals: 1-10, 11-20, 21-30, 31-40, 41-50, and 51 and above. What is wrong with this frequency distribution? a. The interval width is unequal. b. One interval is an open class. c. The class intervals overlap. d. The interval width is too small.
b. One interval is an open class.
A researcher records the number of classroom interruptions during each of two class sessions. Which session has the largest standard deviation?Session A: 12, 15, 18, 24, and 30 Session B: 8, 10, 12, 16, and 20 a. Both samples have the same standard deviation. b. Sample A c. Sample B
b. Sample A
______ refer(s) to how the properties of numbers can change with different uses. a. Operational definition b. Scales of measurement c. Coding d. Measurability
b. Scales of measurement
Assuming N n and all data are otherwise the same, how will the value of the sample variance be different from the population variance? a. The sample variance, but not the population variance, can be zero. b. The sample variance will always be a larger value than the population variance. c. The sample variance, but not the population variance, can be negative. d. The sample variance will always be a smaller value than the population variance.
b. The sample variance will always be a larger value than the population variance.
Which of the following statements about a weighted mean is true? a. The weighted mean is heavier than an arithmetic mean. b. The weighted mean is used to compute the combined mean for two or more samples of scores in which the number of scores in each sample is disproportionate or unequal. c. The weighted mean is always equal to the arithmetic mean. d. The weighted mean can only be reported if the sample size is equal in each group.
b. The weighted mean is used to compute the combined mean for two or more samples of scores in which the number of scores in each sample is disproportionate or unequal.
Given the same set of data for a population and sample, would the mean for both data sets be equal? a. No, the sample mean would be larger. b. Yes, this would be true anytime both data sets are the same. c. No, the population mean would be larger. d. Yes, but only if the sample size equaled the population size.
b. Yes, this would be true anytime both data sets are the same.
A researcher records the following data for how participants rated the likability (on a scale from 1 = not liked at all to 7 = very likable) of an individual who blushed after making a mistake: 5, 4, 7, 6, 6, 4, 6, 7, 2, 5, and 6. Is the mode equal to the median in this example? a. There is not enough information to answer this question. b. Yes. c. No; the mode is larger than the median. d. No; the median is larger than the mode.
b. Yes.
A researcher records the following data for the number of dreams recalled during a night of sleep for 10 college students: 3, 2, 4, 4, 3, 1, 1, 0, 2, and 0. Is the mean equal to the median in this example? a. No; the median is larger than the mean. b. Yes. c. There is not enough information to answer this question. d. No; the mean is larger than the median.
b. Yes.
Which of the following will decrease the value of the mean? a. deleting a score below the mean b. adding a score below the mean c. adding a score exactly equal to the mean d. none of these
b. adding a score below the mean
Which of the following is an example of a distribution with NO variability? a. scores: 3, 5, 4, 4, 5, and 3 b. scores: 5, 5, 5, 5, 5, and 5 c. scores: 1, 2, 3, 4, 5, and 6 d. None of these; all distributions have at least some variability greater than 0.
b. scores: 5, 5, 5, 5, 5, and 5
A researcher reports that the time (in minutes) it takes children who are "picky eaters" to finish their vegetables is negatively skewed, with children finishing their vegetables in 4.2 ± 1.0 (M ± SD) minutes. Based on Chebyshev's theorem, we can conclude that ______. a. 50% of children finished their vegetables in at least 3.2 min b. at least 89% of children finished their vegetables in 1.2-7.2 min c. 99.7% of children finished their vegetables in 2.2-6.2 min d. 68% of children finished their vegetables in 3.2-5.2 min
b. at least 89% of children finished their vegetables in 1.2-7.2 min
A researcher records the number of children at a local school from single-, divorced-, and married-parent homes. These frequency data would be best displayed as a ______. a. ogive b. bar chart c. histogram d. frequency polygon
b. bar chart
Quantitative measures can be ______. a. discrete data b. both A and B c. continuous data
b. both A and B
A researcher reports, "the average patron (n = 22) in a local bar consumed more than twice the number of drinks (per day) on weekends (M = 5.4 drinks) compared to weekdays (M = 2.3 drinks)." Although not stated directly, how do we know that the patrons in this study constitute a sample, and not a population of patrons at this local bar? a. The notation for sample size was used. b. both B and C c. We can't know for sure because this was not stated directly. d. The notation for a sample mean was used.
b. both B and C
Ungrouped data can be distributed as ______. a. intervals b. categories c. upper and lower boundaries d. all of these
b. categories
Adding the same constant to each score in a distribution (or subtracting the same constant from it) will ______. a. not change the mean at all because the same constant was added to or subtracted from each score b. cause the mean to change by that constant
b. cause the mean to change by that constant
The procedure of converting a categorical variable to numeric values, is called ______. a. deteriorating b. coding c. constructing d. piloting
b. coding
The sample variance is computed by dividing SS by ______; whereas the population variance is computed by dividing SS by ______. a. df; n - 1 b. df; N c. n - 1; df d. N; df
b. df; N
Recording the number of dreams recalled is an example of ______ data; whereas recording the time (in minutes) spent in a dream stage of sleep is an example of ______ data. a. qualitative; quantitative b. discrete; continuous c. continuous; discrete d. quantitative; qualitative
b. discrete; continuous
Which of the following research designs is used to determine the causes of behavior that help to explain why the behavior occurs? a. correlational b. experimental c. quasi-experimental d. all of these
b. experimental
Which of the following requires the calculation of a real range? a. frequency distributions for categorical b. frequency distributions for grouped data c. frequency distributions for ungrouped data d. frequency distributions that do not use real data
b. frequency distributions for grouped data
A researcher asks participants to estimate the calories they consume in a meal. The researcher records the following estimates: 450, 426, 310, 500, and 220. If the researcher removes the estimate of 220 (perhaps because the participant drops out of the study), then the value of the mean will ______. a. become negative b. increase c. decrease d. remain the same
b. increase
Procedures that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected best describes ______. a. sample statistics b. inferential statistics c. population parameters d. descriptive statistics
b. inferential statistics
The range of scores between the upper and lower quartiles of a distribution is called the ______. a. quartiles b. interquartile range c. percentiles d. median
b. interquartile range
A researcher measures the body temperature (in degrees Fahrenheit) of participants immediately before and immediately following sleep. Temperature is on what scale of measurement? a. nominal b. interval c. ratio d. ordinal
b. interval
The advantage of squaring the deviation of each score from the mean and then summing is that ______. a. it makes the sample variance an unbiased estimator of the population variance b. it produces a minimal positive solution that is not zero, as long as all scores are not exactly the same value c. it makes the degrees of freedom for sample variance equal to n - 1 d. both A and C
b. it produces a minimal positive solution that is not zero, as long as all scores are not exactly the same value
The ______ is the sum of all scores (in a sample or population) divided by the number of scores summed. a. mode b. mean c. range d. median
b. mean
A researcher asks adult participants to rank their top five favorite songs from their childhood. Based on the scale of measurement described, which measure of central tendency is most appropriate to describe these data? a. mean b. median c. mode d. None; it is inappropriate to describe the central tendency of these data.
b. median
The ______ is the value that occurs most often or at the highest frequency in a distribution. a. range b. mode c. median d. mean
b. mode
State the four scales of measurement in order from least informative to most informative. a. nominal, ordinal, ratio, interval b. nominal, ordinal, interval, ratio c. ordinal, nominal, interval, ratio d. ordinal, nominal, ratio, interval
b. nominal, ordinal, interval, ratio
A consultant ranks the five most needed areas of improvement for a local business. What scale of measurement are the rankings? a. nominal b. ordinal c. interval d. ratio
b. ordinal
Three key elements of control that allow researchers to draw cause-and-effect conclusions are __________. a. randomization, condition, and comparison/control b. randomization, manipulation, and comparison/control c. assignment, manipulation, and comparison/control d. randomization, manipulation, and variation
b. randomization, manipulation, and comparison/control
The median would be used to describe which of the following variables? a. brand name b. rankings c. ethnicity d. gender
b. rankings
A graphical display for grouped frequency distributions with continuous data is called a ______. a. pie chart b. bar chart c. scatter gram d. histogram
d. histogram
A researcher selects a sample of 6 men and 11 women. She asks participants to rate the likelihood they would do female-stereotyped jobs (such as nursing or school teaching) on a scale from 1 = not likely at all to 5 = very likely. Men indicated that they would be less likely to do these jobs (M = 2.1) compared with women (M = 4.3). What is the weighted mean for the combined sample of 17 total participants? a. 2.1 b. 4.3 c. 3.5 d. 3.2
c. 3.5
A researcher computes the computational formula for SS, as finds that = 22 and = 126. If this is a sample of four scores, then what would SS equal using the computational formula? a. 104 b. not possible to know because the sample mean is not given c. 5 d. 4
c. 5
A researcher computes the definitional formula for SS, as finds that E(x-M)2= 112. If this is a sample of 20 scores, then what would the value of population variance be using the definitional formula? a. 112 b. 5.9 c. 5.6 d. not possible to know because the scores are not given
c. 5.6
A psychologist treats 16 patients and records the number of sessions required to complete a behavioral therapy treatment for each patient. She computes SS = 800. Assuming the 16 patients constitute all patients under her care (so the population of her patients), what is the standard deviation for these data? a. 7.3 sessions b. 50 sessions c. 7.1 sessions d. 53.3 sessions
c. 7.1 sessions
A researcher measures the time (in seconds) it takes a sample of 26 participants to respond to a stimulus presented on a computer screen. The standard deviation for response times is 6. In this example, what is the value for SS? a. 36 b. There is not enough information to answer this question. c. 900 d. 150
c. 900
A researcher records the sound (in decibels) during a series of lessons taught by a substitute teacher at a local elementary school. In his study, he found that the sound was 80 ± 6 (M ± SD) decibels. Assuming the data are normally distributed, which of the following is an appropriate conclusion? a. At least 68% of classes were between 76 and 84 decibels. b. At least 5% of classes were louder than 68 decibels. c. At least 95% of classes were between 68 and 92 decibels. d. all of these
c. At least 95% of classes were between 68 and 92 decibels.
A researcher records the following motor assessment scores for two samples of athletes. Which sample has the largest standard deviation?Sample A: 8, 10, 12, 15, and 18 Sample B: 16, 18, 20, 23, and 26 a. Sample B b. Sample A c. Both samples have the same standard deviation.
c. Both samples have the same standard deviation.
______ are measured along a continuum at any place beyond the decimal point. a. Open-ended data b. Qualitative data c. Continuous data d. Discrete data
c. Continuous data
Why is it important to divide by df to compute sample variance? a. It is not important; there is no advantage for dividing by df. b. Doing so ensures that the value for sample variance varies between 0 and 1. c. Doing so makes the sample variance an unbiased estimator of the population variance. d. Doing so minimizes the likelihood that the sample variance will be a negative value.
c. Doing so makes the sample variance an unbiased estimator of the population variance.
______ is the variable in an experiment that is manipulated between conditions being observed. a. Dependent variable b. Quasi-independent variable c. Independent variable
c. Independent variable
A researcher records the number of individual instruments identified by students listening to a piece of classical music. He splits the data into quartiles and reports that students correctly identified three instruments at the 25th percentile, five instruments at the 50th percentile, and eight instruments at the 75th percentile. What are the IQR and SIQR for these data? a. The IQR is 5; the SIQR is 5.0. b. There is not enough information to answer this question. c. The IQR is 5; the SIQR is 2.5. d. The IQR is 3; the SIQR is 1.5.
c. The IQR is 5; the SIQR is 2.5.
How is the sample variance computed differently from the population variance? a. Only one formula includes a computation for SS. b. The calculation in the numerator is different. c. The calculation in the denominator is different. d. None of these; the sample variance and population variance are computed the same.
c. The calculation in the denominator is different.
Researchers rarely have access to entire populations. How do researchers resolve this limitation? a.They record data from an entire population of people to make inferences concerning characteristics in a sample. b. They do not need to resolve this; it is not a limitation at all. c.They record data from a sample of people in the larger population in order to make inferences concerning characteristics in that larger population. d.They record data from as many persons in a population as possible to draw conclusions concerning only those individuals.
c. They record data from a sample of people in the larger population in order to make inferences concerning characteristics in that larger population.
When would it be appropriate to calculate a population mean? a. When it is not possible to measure all data in a population. b. When the sample mean is not available. c. When data are measured for all members of a population. d. When data are measured for a portion of individuals from a population.
c. When data are measured for all members of a population.
A researcher records the following data for the number of different food items chosen by seven participants in a buffet-style setting: 1, 6, 2, 5, 4, 3, and 7. Is the mean equal to the median in this example? a. No; the mean is larger than the median. b. There is not enough information to answer this question. c. Yes. d. No; the median is larger than the mean.
c. Yes.
The SIQR can be defined as ______. a. the range of a distribution divided into half b. the IQR of a distribution plus the range c. a measure of half the distance between Q3 and Q1 d. all of these
c. a measure of half the distance between Q3 and Q1
A percentile is ______. a. a raw score multiplied by 100 b. only used with ungrouped data c. a percentile point d. a value between -1 and +1
c. a percentile point
Suppose that a researcher is interested in a group of 10 million people who paid to see a movie playing in theaters. In this example, the 10 million moviegoers would be regarded as ______. a. a sample of moviegoers who paid to see the movie in a theater b. a dependent variable c. a population of moviegoers who paid to see the movie in a theater d. an independent variable
c. a population of moviegoers who paid to see the movie in a theater
The following is a simple frequency distribution table. Suppose we convert this table to a cumulative frequency distribution. The frequencies in each interval of the cumulative frequency distribution would be a. 5, 8, 10, 14, 20 (top-down summary) b. 6, 10, 12, 15, 20 (bottom-up summary) c. both A and B, depending on how the data were summarized d. It is not possible to summarize the data using a cumulative frequency distribution.
c. both A and B, depending on how the data were summarized
A researcher records the number of votes for each of five candidates running for class president. Based on her presentation of the following results (table), what type of statistics did she use? a. inferential statistics b. deceptive statistics c. descriptive statistics d. population statistics
c. descriptive statistics
The mean would be used to describe which of the following variables? a. model of car b. rankings c. distance traveled in miles d. gender
c. distance traveled in miles
Each of the following are interval scale measurements, except ______. a. the body temperature (in degrees Fahrenheit) increase during exercise b. scores on an SAT (scholastic assessment test) c. duration of sleep (in hours) d. the latitude and longitude of birth for those suffering from schizophrenia
c. duration of sleep (in hours)
The three steps for constructing a simple frequency distribution are ______. a. find the observed range, find the interval width, and construct the frequency distribution b. find the real range, count the scores, and construct the frequency distribution c. find the real range, find the interval width, and construct the frequency distribution d. all of these
c. find the real range, find the interval width, and construct the frequency distribution
A therapist observes that spouses are more likely to forgive their partners for lying to them if they find out the truth from their spouse and not a third party. In this example, the dependent variable is ______. a. the spouse b. the number of partners c. forgiveness d. lying
c. forgiveness
Interval scales of measurement ______. a. have a true zero b. both A and B c. have equidistant scales
c. have equidistant scales
The range of scores in each interval of a grouped frequency distribution is called the _______. a. real range b. grouped data c. interval width d. simple frequency
c. interval width
The ______ is the middle value in a distribution of scores that are listed in numeric order. a. mean b. mode c. median d. range
c. median
The sum of the squared differences of scores from their mean is ______. a. negative b. zero c. minimal d. negligible
c. minimal
A researcher records the hospital admission rates for coronary heart disease at 10 local hospitals. She finds that two different hospitals had the highest overall rates of hospital admissions. Which measure of central tendency did this researcher use to describe these data? a. mean b. median c. mode d. None; it is inappropriate to describe the central tendency of these data.
c. mode
The variance and standard deviation can never be ______. a. larger than the mean b. smaller than the mean c. negative d. zero
c. negative
An animal researcher measures the number of times a rat presses a lever located at the right, center, and left of a cage for a food reward. What scale of measurement is the location of lever pressing? a. interval b. ratio c. nominal d. ordinal
c. nominal
Which of the following terms are least likely to be used to describe qualitative data? a. nominal b. descriptive c. numeric d. categorical
c. numeric
Which graphical display lists percentages and not original scores? a. histogram b. frequency polygon c. ogive d. all of these
c. ogive
The ______ is the percentage of scores with values that fall below a specified score in a distribution. a. interval b. relative frequency c. percentile rank d. percentile point
c. percentile rank
Each of the following is an example of quantitative data, except ______. a. age in years b. weight in ounces c. political affiliation d. income in dollars
c. political affiliation
A characteristic (usually numeric) that describes a population is called a ______. a. sample statistic b. sample c. population parameter d. population
c. population parameter
______ data describe numeric aspects of phenomena; whereas ______ data describe nonnumeric aspects of data. a. continuous; discrete b. discrete; continuous c. quantitative; qualitative d. qualitative; quantitative
c. quantitative; qualitative
To determine the interval width, we divide the ______ by the number of intervals. a. observed range b. exclusive range c. real range d. all of these
c. real range
To construct a pie chart, first distribute the data as ______. a. cumulative frequencies b. cumulative relative percentages c. relative percentages d. cumulative percentages
c. relative percentages
A researcher asks participants to estimate the height (in inches) of a statue that was in a waiting area. The researcher records the following estimates: 40, 46, 30, 50, and 34. If the researcher removes the estimate of 40 (say, due to an experimenter error), then the value of the mean will ______. a. increase b. become negative c. remain the same d. decrease
c. remain the same
Which of the following values is NOT needed to compute sample variance using the computational formula, but is needed to compute the definitional formula? a. scores (x) b. sample size c. sample mean d. degrees of freedom
c. sample mean
Researchers measure data in a ______ to learn more about individuals in the larger ______ of interest. a. statistic; inference b. inference; statistic c. sample; population d. population; sample
c. sample; population
A researcher records 17 scores. What is the median position of these scores? a. the average of the 9th and 10th scores in numeric order b. It's not possible to know this without the raw scores. c. the 9th score in numeric order d. the average of the 8th and 9th scores in numeric order
c. the 9th score in numeric order
The fact that the sum of the differences of scores from their mean is zero best illustrates that ______. a. the mean is equal to zero b. the mean can never be negative c. the mean is the "balance point" of a distribution d. the mean is at the center of a distribution
c. the mean is the "balance point" of a distribution
You are interested in measuring the construct, work expertise. Which of the following measures for this construct is quantitative and discrete? a.the total time in hours spent working at a company b. the job title a person holds in a company c.the number of employees that work under an employee d.the percent of correct responses on a work expertise survey
c. the number of employees that work under an employee
You are interested in measuring the construct, reinforcement. Which of the following measures for this construct is quantitative and continuous? a.the rating of a reward on a scale from 1 (not reinforcing) to 7 (very reinforcing) b. the type of reward (food, money) c. the size of a reward in grams d. the number of rewards received
c. the size of a reward in grams
Which of the following is not a symbol used with samples ______. a. n b. X c. u d. M
c. u
A(n) ______ is a sample statistic that equals a population parameter on average. a. degrees of freedom b. biased estimator c. unbiased estimator d. sum of squares
c. unbiased estimator
Which of the following is the best explanation for why the standard deviation is almost always reported with the mean? a.The mean and standard deviation estimate basically the same thing, so these values are typically reported together. b. This is not true; the standard deviation is rarely reported with the mean. c.The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation. d.The standard deviation is also a measure of central tendency, so it is important to report this value with the mean.
c.The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation.
Measures of variability can range in value from ______. a. - to + b. It depends on the value of the mean for a given distribution. c. It depends on whether the variability is positive or negative. d. 0 to +
d. 0 to + infinity
Which of the following is NOT a characteristic of the mean? a. Delete a score below the mean and the mean will increase. b. Add a score below the mean and the mean will decrease. c. Add a score above the mean and the mean will increase. d. Delete a score above the mean and the mean will increase.
d. Delete a score above the mean and the mean will increase.
Researcher A measures academic preparedness as the percent correct responses on an entrance exam; Researcher B measures academic preparedness as the current class rank of students. Which researcher measured academic preparedness as discrete data? a. both researchers b. Researcher A c. no researchers d. Researcher B
d. Researcher B
A researcher measures the number of trials it takes two samples of participants to master a new task. In both samples, SS = 240. Sample A consisted of 12 participants and Sample B consisted of 18 participants. Which sample is associated with the largest variance? a. Both samples have the same variance. b. There is not enough information to answer this question. c. Sample B d. Sample A
d. Sample A
A researcher distributes frequencies into the following intervals: 3-6, 7-10, 11-15, 16-18, 19-22, and 23-26. What is wrong with this frequency distribution? a. The interval width is too small. b. The first class interval does not begin at 0. c. One interval is an open class. d. The interval width is unequal.
d. The interval width is unequal.
Which of the following is NOT a rule for constructing a simple frequency distribution? a. Each interval is equidistant. b. No class interval overlaps. c. At least five class intervals are included. d. The number of intervals should equal the number of values measured.
d. The number of intervals should equal the number of values measured.
A student scores in the 80th percentile on an exam. What does this mean in comparison to all other students? a. Of all those who took the exam, only 80% of them completed it. b. The student would score the same grade on the exam 80% of the time. c. The student scored worse than 80% of all others who took the exam. d. The student scored higher than 80% of all others who took the exam.
d. The student scored higher than 80% of all others who took the exam.
Which characteristic of a histogram implies that it summaries continuous data? a. The data are plotted on the y-axis. b. The height of the vertical bars are not restricted. c. The x-axis lists data on a nominal scale of measurement. d. The vertical bars touch at the upper boundary of each interval.
d. The vertical bars touch at the upper boundary of each interval.
A researcher selects a sample of six professors, six students, and six administrators at a local school and has them rate the effectiveness of an innovative new teaching style. In this example, is it possible that the weighted mean ratings will equal the arithmetic mean for the entire sample of 18 participants? a. Yes, because the sample sizes are selected from the school equal. b. It is not possible to know this without knowing the mean for each sample. c. No, the weighted mean is never exactly equal to the arithmetic mean. d. Yes, because there are an equal number of participants in each sample.
d. Yes, because there are an equal number of participants in each sample.
A psychologist wants to know how many of her clients continue with therapy for at least 12 days. If she constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer her question? a. a simple frequency distribution b. a relative frequency distribution c. a cumulative frequency distribution from the bottom up d. a cumulative frequency distribution from the top down
d. a cumulative frequency distribution from the top down
A reason for squaring deviations to compute SS in the numerator includes which of the following? a. The sum of the differences of scores from their mean is zero. b. The sum of the squared differences of scores from their mean is minimal. c. Squaring scores can be corrected readily by square rooting. d. all of these
d. all of these
A researcher distributes frequencies into the following classes: absent, tardy, and present. What type of data is distributed? a. nominal data b. qualitative data c. ungrouped data d. all of these
d. all of these
A staff member records the number of victories (per 10-game season) for a new football coach during his first three seasons with a team. The coach won 1, 3, and 8 games, respectively, over the three seasons. Which conclusion is appropriate? a. The football coach won an average of four games per season. b. The football coach won a median of three games per season. c. The football coach won 40% of his games during his first three seasons. d. all of these
d. all of these
Descriptive statistics are procedures used to ______. a. summarize a set of scores or observations b. organize a set of scores or observations c.make sense of a set of scores or observations d. all of these
d. all of these
Grouped data can be distributed ______. a. as a range of values b. with upper and lower boundaries c. into intervals d. all of these
d. all of these
The mean is an appropriate measure of central tendency for ______. a. data that are normally distributed b. data that are on an interval or ratio scale c. data in which the mean, median, and mode are equal d. all of these
d. all of these
The median is an appropriate measure of central tendency for ______. a. data that are positively skewed b. data that are negatively skewed c. data that are on an ordinal scale d. all of these
d. all of these
The mode is an appropriate measure of central tendency for ______. a. data that are bimodal b. use with other measures of central tendency c. data that are on a nominal scale d. all of these
d. all of these
The range, a measure of variability, ______. a. is the difference between the largest (L) and smallest (S) value in a list of scores b. is the most informative when used to describe data sets without outliers c. includes only two values in its computation, regardless of the number of scores in a distribution d. all of these
d. all of these
The sum of the squared deviations of scores from their mean ______. a. is computed the same for samples and populations b. is computed by squaring each deviation to avoid a zero solution in the numerator c. is the numerator for the sample variance and population variance d. all of these
d. all of these
When cumulating frequencies from the bottom up, the data are discussed in terms of ________. a. at most b. less than c. at or below d. all of these
d. all of these
When cumulating frequencies from the top down, the data are discussed in terms of _______. a. greater than b. at or above c. at least d. all of these
d. all of these
When df are in the denominator, the sample variance is ______. a. an unbiased estimator of the population variance b. associated with n - 1 degrees of freedom c. computed by dividing SS by df d. all of these
d. all of these
Which of the following describes the definitional formula for variance? a. It is stated in terms of how variance is defined. b. It is computed using SS in the numerator. c. It is a measure of the average squared distance that scores deviate from their mean. d. all of these
d. all of these
Which of the following is a type of graphical display used to summarize quantitative, continuous data? a. histogram b. frequency polygon c. ogive d. all of these
d. all of these
Which of the following is consistent with the empirical rule? a. At least 68% of all scores lie within one standard deviation of the mean. b. At least 95% of all scores lie within two standard deviations of the mean. c. At least 99.7% of all scores lie within three standard deviations of the mean. d. all of these
d. all of these
Which of the following is true about the computational formula for variance? a.The computational formula will always produce the same solution as the definitional formula (give or take rounding errors). b. It is a shortcut method for calculating variance when the population or sample size is large. c. It is derived mathematically from the definitional formula. d. all of these
d. all of these
A population can be ______ group of interest to a researcher. a. only a small b. only a large c. only one d. any
d. any
The degrees of freedom for the sample variance ______. a. can vary between - and + b. are equal to the sample size c. both B and C d. are equal to the sample size minus one
d. are equal to the sample size minus one
What terms refer to the meaning of each of the following measures, respectively: mean, median, and mode. a. most, average, and middle b. average, most, and middle c. middle, most, and average d. average, middle, and most
d. average, middle, and most
The mathematical term Ex is the numerator for ______. a. the population mean b. None; this term is not in the numerator for any calculation. c. the sample mean d. both A and B
d. both A and B
Qualitative data varies by ______; quantitative data varies by ______. a. amount; class b. value; level c. level; value d. class; amount
d. class; amount
A health practitioner measures the heart rate (in number of beats per minute) of patients under low, moderate, and high stress levels. Heart rate can be best described as ______. a. a qualitative variable b. the independent variable c. discrete data d. continuous data
d. continuous data
Statistical analysis allows researchers to ______. a. claim that an observation is scientific b.study physical phenomena but not behavior c. collect data d. evaluate scientific observations
d. evaluate scientific observations
Three research methods common to research in the behavioral sciences are ______. a. experimental, operational, and quasi-correlational b. experimental, variable, and correlational c. experimental, transferable, and correlation d. experimental, quasi-experimental, and correlational
d. experimental, quasi-experimental, and correlational
A ______ is plotted at the midpoint of each interval, whereas a ______ is plotted at the upper boundary of each interval. a. histogram; bar chart b. frequency polygon; histogram c. histogram; frequency polygon d. frequency polygon; ogive
d. frequency polygon; ogive
A researcher records the time it takes to complete a memory task in a sample of 25 participants. He finds that the average participant completed the test in 43 s. The average time to complete this task is called a(n) ______. a. inferential statistic b. time trial c. population parameter d. sample statistic
d. sample statistic
A researcher records 52 scores. What is the median position of these scores? a. the 26th score in numeric order b. It's not possible to know this without the raw scores. c. the 27th score in numeric order d. the average of the 26th and 27th scores in numeric order
d. the average of the 26th and 27th scores in numeric order
Which of the following best describes an independent variable? a. the population variable b. the measured behavior c. the sample variable d. the manipulated variable
d. the manipulated variable
A measure of the average squared distance of scores from the mean is called the ______. a. IQR b. sum of squares c. range d. variance
d. variance
The ______ is an arithmetic mean of a weighted or disproportionate set of scores. a. mode b. median c. mean d. weighted mean
d. weighted mean