Statistics: Exam 1

Fill in the missing values for A and B in this frequency distribution table Intervals Frequency 6.0-6.6 12 5.3-5.9 7 4.6-5.2 B 3.9-4.5 10 A-3.8 8 N=50

A=3.2 B=13

A percentile is

A Percentile Point

The sum of the squared differences of scores from their mean is

Minimal

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 5th percentile, and a score of 80 is at the 75th percentile. What is the interquartile range (IQR) for these data?

16

A researcher computes the computational formula for SS, and finds that Ex=39 and Ex^2=271. If this is a sample of 6 scores, then what would the SS equal using the definitional formula?

17.5

A researcher finds that 12% of participants make between 3-5 visits to a physician each year. What are the real limits for this interval?

2.5-5.5

As a general rule, a simple frequency distribution should have between

5 and 20 intervals

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?

Histogram

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?

Histogram

__________ is the variable in an experiment that is manipulated between conditions being observed

Independent Variable

A researcher records the hospital admission rates for coronary heart disease at 10 local hospitals. She finds that 2 different hospitals had the highest overall rates of hospital admissions. Which measure of central tendency did this researcher use to describe these data?

Mode

The ______ is the value that occurs most often or at the highest frequency in a distribution

Mode

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?

No; the median is larger than the mode

A researcher records the following data (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?

No; the mode is larger than the mean

State the four scales of measurement in order from least informative to most informative

Nominal, Ordinal, Interval, Ratio

A researcher compares the amount of college debt (in dollars) that undergraduate students incur up to their four-year degree. College debt is on what scale of measurement?

Ratio

Which of the following can be used to estimate the median?

The 50th percentile of a cumulative percentage distribution

What best describes a dependent variable?

The measured behavior

Ungrouped data can be distributed as

Categories

__________ are measured in whole units or categories that are not distributed along a continuum

Discrete Data

Which graphical display lists percentages and not original scores

Ogive

A consultant ranks the five most needed areas of improvement for a local business. What scale of measurement are the rankings?

Ordinal

A movie critic rates a movie on a scale from one (lowest) to four (highest) stars. What scale of measurement are the ratings?

Ordinal

The mean is an appropriate measure of central tendency for -Data that are normally distributed -Data that are on an interval or ratio scale -Data in which the mean, median, and mode are equal -All of the above

All of the above

Qualitative data varies by _________; Quantitative data varies by __________

Class; Amount

Based on the following graphical summary display, what research design was used to record and analyze these data? -Picture is of a graph with multiple points and a line of best fit

Correlational

The three steps for constructing a simple frequency distribution are

Find the real range, Find the interval width, Construct the frequency distribution

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?

Mean

The ________ is the sum of all scores (in a sample or population) divided by the number of scores summed

Mean

The _______ is the middle value in a distribution of scores that are listed in numeric order

Median

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

Sample A

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

Sample B

Which of the following values is NOT needed to compute sample variance using the computational formula, but is needed to compute the definitional formula?

Sample Mean

Which type of mean is used to describe a portion of individuals in a give population?

Sample Mean

A characteristic (usually numeric) that describes a sample is called a

Sample statistic

Which of the following is an example of a distribution with NO variability? -Scores: 5, 5, 5, 5, 5, and 5 -Scores: 3, 5, 4, 4, 5, and 3 -Scores: 1, 2, 3, 4, 5, and 6

Scores: 5, 5, 5, 5, 5, and 5

Which describes a descriptive statistic?

Summarize

What is the corresponding percentile of a percentile point

The Percentile Rank

Bar charts are a lot like histograms, except

The bars displayed in the graph do not touch

Grouped data can be distributed: -As a range of values -With upper and lower boundaries -Into intervals -All of the above

All of the Above

A researcher summarizes a set of frequency data into five intervals. This is an example of a frequency distribution for

Grouped Data

A graphical display for grouped frequency distributions with continuous data is called a

Histogram

Each of the following are interval scale measurements, except: -Duration of sleep (in hours) -Marital satisfaction of ratings on a 5-point rating scale -The latitude and longitude of birth for those suffering from schizophrenia -The body temperature (in degrees Fahrenheit) increase during exercise

Marital satisfaction ratings on a 5-point rating scale

A percentile is also called a

Percentile Point

A cumulative percentage summary that indicates the percentage of scores at or below a given value is called a

Percentile rank

You are interested in measuring the construct, reinforcement. Which measure for this construct is quantitative and continuous?

The size of rewards in grams

Regardless of the number of scores in a distribution, the range only includes ____ score(s) in its calculation

Two

What is the percentile point at the 80th percentile in the following distribution? Frequency Percentile Rank 9-11 100% 6-8 80% 3-5 40% 0-2 20%

8

What is the percentile point at the 90th percentile in the following distribution? 9-11: 100% 6-8: 80% 3-5: 40% 0-2: 20%

9.5

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?

900

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 cumulative frequency distribution from the top down

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 population of moviegoers who paid to see the movie in a theater

Which of the following is not a symbol used with samples: -x -M -u -n

u

The population mean is symbolized as _________, whereas the sample mean is symbolized as _______.

u; M

The size of a population is symbolized as _________, whereas the size of a sample is symbolized as ______

N;n

_____________ data describes numeric aspects of phenomena; whereas ________ data describes non-numeric aspects of data

Quantitative; Qualitative

A relative frequency distribution is appropriate when

There are large frequency counts in each interval

Researchers rarely have access to entire populations. How do researchers resolve this limitation?

They record data from a sample of people in their larger population in order to make inferences concerning characteristics in that larger population.

Which of the following statements about a weighted mean is true?

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

Which of the following is a type of graphical display used to summarize quantitative, continuous data? -Histogram -Frequency Polygon -Ogive -All of the Above

All of the Above

The median is an appropriate measure of central tendency for -Data that are positively skewed -Data that are negatively skewed -Data that are on an ordinal scale -All of the above

All of the above

The sample variance is -An unbiased estimator of the population variance -Associated with n-1 degrees of freedom -Computed by dividing SS by df -All of the above

All of the above

Which of the following will decrease the value of the mean?

Adding a score below the mean

A reason for squaring deviations to compute SS in the numerator includes which of the following? -The sum of the differences of scores from their mean is zero -The sum of the squared differences of scores from their mean is minimal -Squaring scores can be corrected easily by square rooting -All of the above

All of the above

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 one 1, 3, and 8 games respectively over the three seasons. Which conclusion is appropriate? -The football coach won an average of four games per season -The football coach won a median of 3 games per season -The football coach won 40% of his games during his first three seasons -All of the above

All of the above

Descriptive statistics are procedures used to: -Summarize a set of scores or observations -Organize a set of scores or observations -Make sense of a set of scores or observations -All of the above

All of the above

Which of the following are consistent with the empirical rule? -68% of all scores lie within one standard deviation of the mean -95% of all scores lie within two standard deviations of the mean -99.7% of all scores lie within three standard deviations of the mean -All of the above

All of the above

Which of the following describes the definitional formula for variance? -It is stated in terms of how variance is defined -It is computed using SS in the numerator -It is a measure of the average squared distance that scores deviate from their mean -All of the above

All of the above

Which of the following is true about the computational formula for variance? -The computational formula will always produce the same solution as the definitional formula (give or take rounding errors) -It is a short-cut method for calculating variance when the population of sample size is large -It is derived mathematically from the definitional formula -All of the above

All of the above

_______________ are measured along a continuum at any place beyond the decimal point

Continuous Data

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

Both samples have the same standard deviation

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

Both samples have the same standard deviation

Adding the same constant to each score in a distribution (or subtracting the same constant from it) will

Cause the mean to change by that constant

Multiplying or dividing each score in a distribution by the same constant will

Cause the mean to change by that constant

Which of the following is NOT a characteristic of the mean? -Add a score above the mean and the mean will increase -Add a score below the mean and the mean will decrease -Delete a score below the mean and the mean will increase -Delete a score above the mean and the mean will increase

Delete a score above the mean and the mean will increase

_________ is the variable that is believed to change the presence of the independent variable

Dependent Variable

The use of tables and graphs to summarize data is an example of

Descriptive Statiscis

Quantitative measures can be

Discrete and continuous data

Recording the number of dreams is called an example of ____________ data; whereas recording the time (in minutes) spent in a dream stage of sleep is an example of__________ data.

Discrete; Continuous

The mean would be used to describe with of the following variables? -Rankings -Distance in miles -Gender -Model of car

Distance in miles

Why is it important to divide df to compute sample variance?

Doing so makes the sample variance an unbiased estimator of the population variance

The definitional formula __________ the computational formula for SS

Equals

Statistical analysis allows researchers to

Evaluate scientific observations

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

Experimental

Which research design is used to determine the causes of behavior that help to explain why the behavior occurs?

Experimental

Three research methods common to research in the behavioral sciences are

Experimental, Quasi-Experimental, and Correlational

A researcher records the following data: 4, 4, 4, 4, and 3. How would you describe the variability of the data?

It is very small (close to 0) because scores are approximately the same

The advantage of squaring the deviation of each score from the mean and then summing is that

It produces a minimal positive solution that is not zero, so long as all the scores are not the same value

The distribution of personal income for U.S. citizens is positively skewed. If the median annual income is $44, 000, this implies that the mean annual income is

Larger

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?

No; the mean is larger than the median

A researcher records a sample of 30 exam scores and finds that the population variance for these data is larger than the sample variance. Is this possible?

No, the sample variance will be larger because SS is divided by degrees of freedom in the denominator of the variance formula

Each of the following is an example of quantitative data, except -Weight in ounces -Income in dollars -Political affiliation -Age in years

Political Affiliation

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

Population Parameter

A characteristic (usually numeric) that describes a population is called 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

Qualitative; Quantitative

Grouped data are to ungrouped data as

Quantitative is to qualitative

To determine the interval width, we divide the _________ by numbers of intervals

Real Range

To construct a pie chart, first distribute the data as

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), the the value of the mean will

Remain the same

If a portion of people from a population are asked to complete an assessment, the the average score among that group of people would be considered a

Sample Mean

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 seconds. The average time to complete this task is called a(n)

Sample statistic

Researchers measure data in a _________ to learn more about individuals in the larger _________ of interest

Sample; Population

_________ refers to how the properties of numbers can change with different uses

Scales of Measurement

Which of the following distributions has the largest variability? -Scores: 1, 3, 6, 9, and 12 -Scores: 22, 24, 26, 28, and 30 -Scores: 2, 3, 4, 5, and 6 -Scores: 1, 2, 3, 4, and 5

Scores: 1, 3, 6, 9, and 12

State the problem with this simple frequency distribution Intervals Frequency 8-10 4 6-8 7 4-6 3 2-4 6 0-2 9

The class intervals overlap

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?

The interval width is unequal

A researcher distributes frequencies into the following intervals; 1-1-, 11-20, 21-30, 31-40, 41-50, and 51 and above. What is wrong with this frequency distribution?

The interval width is unequal

What best describes an independent variable?

The manipulated variable

The fact that the sum of the differences of scores from their mean is zero best illustrates that

The mean is the "balance point" of a distribution

A researcher reports that "the average shopper in a sample (n=12) purchased $65.00 worth of items (u=$65.00) during a busy shopping day." What mistake was made in this citation?

The sample mean is written using the wrong notation

All other things being equal, how will the value of the sample variance be different from the population variance?

The sample variance will always be a larger value than the population variance.

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

The small group of college students who were observed

Which of the following is the best explanation for why the standard deviation is almost always reported with the mean?

The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation

A(n) __________ is a sample statistic that equals a population parameter on average

Unbiased estimator

The following frequency distribution is an example of Household TV's f(x) 5 4 4 23 3 20 2 29 1 30 0 8

Ungrouped Data

A measure of the average squared distance of scores from the mean is called the

Variance

The mode can be used with the mean to describe which of the following variables?

Volume in a container

Each deviation in the numerator for variance is squared because

Without squaring each deviation, the solution for SS would be zero

The ______ is an arithmetic mean of a weighted or disproportionate set of scores

Weighted Mean

When would a researcher calculate a population mean?

When data are measured for all members of a population

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?

Yes

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?

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?

Yes

A researcher selects a sample of 6 professors, 6 students, and 6 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?

Yes, because the sample sizes are equal in this example

The sample variance is computed by dividing SS by ______; whereas the population variance is computed by dividing SS by_____

df;N

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 figure represent?

df=23; it represents the number of scores that are free to vary in a sample

Measures of variability can range in value from

0 to +infinity

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

1.0 (9.9 to 8.9)

The sum of relative frequencies for each interval is

1.00

A researcher reports that 12 people in a sample of 60 reported getting between 4 and 6 hours of sleep per night. What is the relative percentage for this interval?

20%

The following is a simple frequency distribution table. If we convert this frequency distribution to relative percentages, which of the following gives the corresponding percentages in each interval listed from the top down? Intervals Frequency 44-46 6 41-43 4 30-40 5 35-37 10 32-34 5 N=30

20%, 13%, 17%, 33%, 17%

What is the percentile point at the 50th percentile for the following distribution? Intervals Frequency 31-35 9 26-30 11 21-25 12 35-37 8

25

A researcher selects a sample of 6 males and 11 females. 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 this entire sample of 17 participants?

3.5

A researcher computes the definitional formula for SS, and 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 computational formula?

4.0

A researcher computes the computational formula for SS, and finds that Ex=22 and Ex^2=126. If this is a sample of 4 scores, then what would the SS equal using the definitional formula?

5

A researcher computes the definitional formula for SS, and 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 computational formula?

5.6

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?

7.1 seconds

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?

7.1 sessions

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 + or - 6 (M+or-SD) decibels. Assuming the data are normally distributed, which of the following is an appropriate conclusion?

95% of classes were between 68 and 92 decibels

A researcher wants to determine how many participants will take less than 24 seconds 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 cumulative frequency distribution from the bottom up

The SIQR can be defined as

A measure of half the distance between Q3 and Q1

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+ or -1.0 (M+or-SD) minutes. Based on Chebyshev's theorem, we can conclude that

At least 89% of children finished their vegetables in 1.2 to 7.2 minutes

What terms refer to each of the following measures, respectively: mean, median, and mode

Average, Middle, and Most

State the type of graphical display for Graph A and Graph B: -Graph A has bars that touch -Graph B has bars that do not touch

B is a bar chart; A is a histogram

A researcher records the number of children at a local school from single, divorced, and married parent homes. This frequency data would be best displayed as a

Bar Chart

The procedure of converting a categorical variable to numeric values, is called

Coding

A researcher records the number of votes for each of five candidates running for class president. Based on her presentation of the following results, what type of statistics did she use? -Candidate-Number of Votes -A-120 -B-125 -C-42 -D-203 -E-20

Descriptive StatisticsA he

A health practitioner measures the heart rate (in beats per minute) of patients under low, moderate, and high stress levels. Heart rate can be best described as

Discrete Data

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

Forgiveness

Which of the following requires the calculation of a real range?

Frequency distributions for grouped data

Interval scales of measurement

Have equidistant scales

Procedures that allow researchers to infer to generalize observations made with samples to the larger population from which they were selected best describes

Inferential Statistics

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?

Median

Which of the following terms are least likely to be used to describe qualitative data? -Nominal -Descriptive -Categorical -Numeric

Numeric

The _______ is the percentage of scores with values that fall below a specified score in a distribution, is called the

Percentile Rank

Three elements of control that allow researchers to draw cause-and-effect conclusions are

Randomization, Manipulation, and Comparison/Control

The median would be used to describe which of the following variables?

Rankings

Researcher A measures academic preparedness as the percent correct responses on an exam; Researcher B measures academic preparedness as the current class rank of students. Which researcher measured academic preparedness as discrete data?

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?

Sample A

A researcher records 17 scores. What is the median position of these scores?

The 9th score in numeric order

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 3 instruments at the 25th percentile, 5 instruments at the 50th percentile, and 8 instruments at the 75th percentile. What are the IQR and SIQR for these data?

The IQR is 5; the SIQR is 2.5

A researcher records 52 scores. What is the median position of these scores?

The average of the 26th and 27th scores in numeric order

How is the sample variance computed differently from the population variance?

The calculation in the denominator is different

You are interested in measuring the construct, work expertise. Which measure for this construct is quantitative and discrete?

The number of employees that work under an employee

Which of the following is not a rule for constructing a simple frequency distribution? -The number of intervals should equal the number of values measured -Each interval is equidistant -No class interval overlaps -Values are rounded to the same degree of accuracy measured in the original data

The number of intervals should equal the number of values measured

Which measure of attraction is an example of a ratio scale measurement

The physical proximity (in feet and inches) between two romantic partners

A student scores in the 80th percentile on an exam. What does this mean in comparison to all other students?

The student scored higher than 80% of all others who took the exam

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%?

The sum of differences is equal to zero

An interquartile range removes

The top and bottom 25% of scores in a distribution before calculating range

A percentile point is

The value of a score on a measurement scale below which a specified percentage of scores in a distribution fall

Given the same set of data for the population and sample, would the mean for both data sets be equal?

Yes, this would be true anytime both data sets are the same

A population can be ____ group of interest to a researcher

Any

The mathematical term Ex is the numerator for -The population mean -The sample mean -Both A and B -None; this term is not in the numerator for any calculation

Both A and B

Which of the following is a type of graphical display used to summarize qualitative, discrete data? -Bar Chart -Pie Chart -Histogram -Both A and B

Both A and B

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: Intervals Frequency 17-20 5 13-16 3 9-12 2 5-8 4 1-4 6 -5, 8, 10, 14, 20 (top down summary -6, 10, 12, 15, 20 (bottom up summary) -Both A and B, depending on how the data were summarized -It is not possible to summarize the data using a cumulative frequency distribution

Both A and B, depending on how the data were summarized

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 populations of patrons at this local bar? -We can't know for sure because this was not stated directly -The notation for a sample mean was used -The notation for a sample size was used -Both B and C

Both B and C

A _________ is plotted at the midpoint of each interval, whereas a __________ is plotted at the upper boundary of each interval

Frequency polygon; Ogive

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 seconds) completed the task more quickly than Group B (M=36 seconds). 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?

Group A

The variance and standard deviation can never be

Negative

A researcher distributes frequencies into the following classes: absent, tardy, present. What type of data are distributed? -Nominal data -Qualitative data -Ungrouped data -All of the above

All of the Above

A simple frequency distribution: -Can be used to summarize grouped data -Can be used to summarize ungrouped data -Summarized the frequency of scores in a give category or range -All of the above

All of the Above

The sum of the squared deviations of scores from their mean: -Is computed the same for samples and populations -Is computed by squaring each deviation to avoid a zero solution in the numerator -Is the numerator for the sample variance and population variance -All of the above

All of the above

When cumulating frequencies from the bottom up, the data are discussed in terms of -At most -At least -At or below -All of the above

All of the above

The degrees of freedom for the sample variance

Are equal to the sample size minus one

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

60

When cumulating frequencies from the top down, the data are discussed in terms of: -Greater than -At or above -At least -All of the above

All of the Above

The mode is an appropriate measure of central tendency for -Data that are bimodal -Use with other measures of central tendency -Data that are on a nominal scale -All of the above

All of the above

The range, a measure of variability -Is the difference between the largest (L) and smallest (S) value in a list of scores -Is the most informative when used to describe data sets without outliers -Includes only two values in its computation, regardless of the number of scores in a distribution -All of the above

All of the above

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

Increase

The range of scores between the upper and lower quartiles of a distribution is called the

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?

Interval

The range of scores in each interval of a grouped frequency distribution is called the

Interval Width

Grouped date are distributed into ________, whereas ungrouped data are distributed into ___________

Intervals; Categories

A researcher measures the amount of coffee consumed by college students while studying during final exam week. In her study, she found that students drink 2.3+or-0.8 (M+or-SD) cups of coffee per study session. Assuming the data are normally distributed, which of the following is the most appropriate conclusion?

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 -The standard deviation varies between - infinity and +infinity -The standard deviation is used to describe qualitative variables -Multiplying each score times the same constant will change the standard deviation by that constant -Adding the same constant to each score will change the standard deviation by that constant

Multiplying each score times the same constant will change the standard deviation by that constant

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?

No; the mode is larger than the median

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?

Nominal

An education counselor records the number of high school graduates enrolled in community colleges, four-year colleges, and universities. What scale of measurement is the type of college?

Nominal

All other things being equal (so assuming that the value of SS never changes) as sample size increases,

The value of sample variance decreases

Which characteristic of a histogram implies that it summaries continuous data

The vertical bars touch at the upper boundary of each interval