Chapter 13 Study Questions

The horizontal axis of a graph is called the _____. A. abscissa or x-axis B. abscissa or y-axis C. ordinate or x-axis D. ordinate or y-axis

abscissa or x-axis

Why is it a good idea to explore your data using EDA techniques before you conduct any statistical tests? A. They help spot serious defects in your data that may warrant taking corrective action before you proceed to the inferential analysis. B. They can help you determine which summary statistics would be appropriate for a given set of data. C. They may reveal unsuspected influences. D. All of the answers are correct.

all of the answers are correct

The _____ is the most sensitive measure of center because it takes into account all scores in a distribution when it is calculated. A. median B. mode C. interquartile range D. arithmetic average

arithmetic average

Dummy coding involves: A. assignment of numbers to the levels of a qualitative independent variable. B. creating new variables based on the values of the old ones. C. categorizing dependent variables according to their magnitudes. D. None of the answers is correct.

assignment of numbers to the levels of a qualitative independent variable.

When a curve levels off at some maximum or minimum value, the function is said to be _____ at that value. A. nonlinear B. nonmonotonic C. positively accelerated D. asymptotic

asymptotic

In a distribution with an even number of scores, the median is determined by: A. finding the most frequent score in the top half of the distribution and averaging it with the most frequent score in the bottom half of the distribution. B. finding the arithmetic average of the entire distribution and dividing it by two. C. averaging the middle pair of scores. D. finding the most frequent score.

averaging the middle pair of scores.

You can display the five-number summary graphically as a: A. histogram. B. bar graph. C. boxplot. D. scatter plot.

boxplot

A bar graph is the best method of graphing data when your independent variable is: A. scaled on an interval scale. B. scaled on a ratio scale. C. continuous. D. categorical.

categorical.

A distribution contains the following scores: 1, 1, 2, 2, 2, 3, 3, 4, 4, 5. Its mode is: A. 5. B. 3. C. 2. D. 4.

2

A distribution contains the following scores: 1, 1, 2, 2, 2, 3, 3, 4, 4, 5. Its mean is: A. 2.5. B. 2.7. C. 2.0. D. 4.0.

2.7

The simplest and least informative measure of spread is the: A. standard deviation. B. variance. C. range. D. interquartile range.

range

The difference between Y and Ŷ is a: A. residual. B. remainder. C. regression deviation. D. difference.

residual.

A high value of the coefficient of nondetermination means that: A. there is a causal relationship between variables. B. performing linear regression is unnecessary. C. you can expect a large change in X as a function of Y. D. None of the answers is correct.

None of the answers is correct.

A correlation matrix results when you: A. compute all possible correlations among a number of variables. B. enter your scores into a linear regression analysis. C. compute beta weights for all your variables. D. None of the answers is correct.

compute all possible correlations among a number of variables.

The median is a rather insensitive measure of center because it: A. is difficult to calculate. B. does not take into account the magnitudes of the scores above and below it. C. cannot be used with interval data. D. All of the answers are correct.

does not take into account the magnitudes of the scores above and below it.

For data measured on a nominal scale, you are limited to using the _____ as your measure of center. A. mean B. mode C. median D. All of the answers are correct.

mode

A curve that represents a uniformly increasing or decreasing function is said to be: A. monotonic. B. nonmonotonic. C. cubic. D. asymptotic.

monotonic.

Extreme scores that lie far from the others in a distribution are called: A. deviants. B. distant scores. C. outlaws. D. outliers.

outliers.

In a positively skewed distribution, the mean: A. underestimates the center. B. overestimates the center. C. is as accurate a measure of the center as is the median. D. accurately represents central tendency.

overestimates the center.

Pairs of scores from a correlational study are usually represented as points on a: A. histogram. B. scatter plot. C. line graph. D. pie graph.

scatter plot.

The _____ of a correlation coefficient tells you the direction of a relationship, whereas the _____ tells you the degree of linear relationship between two variables. A. magnitude; sign B. value; magnitude C. sign; magnitude D. None of the answers is correct.

sign; magnitude

The most popular measure of spread is the: A. standard deviation. B. variance. C. interquartile range. D. range.

standard deviation

In the formula that describes the regression line mathematically, b is: A. a constant. B. the regression weight. C. a predicted score. D. the same as the Pearson r.

the regression weight.

The standard error of estimate increases as: A. beta decreases. B. the strength of the relationship between X and Y increases. C. the strength of the relationship between X and Y decreases. D. the constant in the regression equation increases.

the strength of the relationship between X and Y decreases.

In the context of the measures of spread, the _____ is the average squared deviation from the mean. A. standard deviation B. variance C. range D. interquartile range

variance

Graphing data, rather than presenting them in a table, is important when you: A. want to show relationships clearly. B. are choosing appropriate statistics. C. are contemplating not using descriptive statistics. D. want to show relationships clearly and when choosing appropriate statistics.

want to show relationships clearly and when choosing appropriate statistics.

When graphing data from an experiment, levels of an independent variable are normally represented along the: A. y-axis. B. x-axis. C. z-axis. D. ordinate.

x-axis

In a stemplot of scores ranging from 11 to 83, a score of 42 would be located at a stem value of _____. A. 4 B. 6 C. 40 D. 2

4

When examining a histogram or stemplot of your data, you should: A. locate the center of the distribution along the scale of measurement. B. note the spread of the scores. C. note the overall shape of the distribution and look for any gaps or outliers. D. All of the answers are correct.

All of the answers are correct.

_____ resemble bar graphs, with each bar representing a class, and a given bar's length indicating the frequency of scores falling within its range. A. Histograms B. Scatter plots C. Exploded pie graphs D. Stemplots

Histograms

Identify a true statement about an unstacked format, which is a way of organizing data from experimental or quasi-experimental designs. A. This format is appropriate when data include multiple independent or dependent variables. B. This format fails to display treatment summary statistics in a simple way. C. In this format, multiple columns of subject numbers are needed. D. In this format, a separate column is created for the scores from each treatment.

In this format, a separate column is created for the scores from each treatment.

Which of the following is a disadvantage of a stacked format? A. It makes it difficult to include additional columns to indicate the observed values of additional variables. B. It fails to accommodate complex designs involving several quasi-independent variables. C. It does not provide a simple way to display treatment summary statistics. D. It is not an acceptable format for many computer statistical analysis packages.

It does not provide a simple way to display treatment summary statistics.

Which of the following statements is true about a bar graph? A. In this graph, each pair of scores is represented as a point on the graph. B. It is most appropriate when the independent variable is continuous and quantitative. C. In this graph, the width of each bar reflects the value of the dependent variable. D. It presents data as bars extending away from the axis representing the independent variable.

It presents data as bars extending away from the axis representing the independent variable.

Which of the following is the major advantage of the mean? A. Its value is directly affected by the magnitude of each score in a distribution. B. Its insusceptibility to the influence of outliers makes it highly reliable. C. It is an appropriate measure of center when data are measured on an ordinal scale. D. It is the most preferred measure whenever a distribution is strongly skewed.

Its value is directly affected by the magnitude of each score in a distribution.

_____ are more appropriate than bar graphs when your independent variable is continuous and quantitative. A. Line graphs B. Scatter plots C. Pie graphs D. All of the answers are correct.

Line graphs

Which of the following is the most widely used measure of association and is appropriate when the dependent measures are scaled on an interval or a ratio scale? A. The point-biserial correlation B. The phi coefficient C. The Spearman rank-order correlation D. The Pearson r

The Pearson r

Which of the following measures of spread is easy to calculate and is resistant to the effects of skew and outliers? A. The standard deviation B. The variance C. The interquartile range D. The range

The interquartile range

In a bar graph, the length of each bar reflects the value of the: A. independent variable. B. abscissa. C. dependent variable. D. quasi-independent variable.

dependent variable

Although mode is simple to calculate, it is limited because it: A. is insensitive to extreme scores. B. is difficult to compute. C. is inappropriate for use with interval data. D. does not take into account the values of scores outside of the most frequent score.

does not take into account the values of scores outside of the most frequent score.

If categories are represented by numbers (e.g., 1 = Democrat, 2 = Republican), the categories are said to be: A. dummy-coded. B. nominalized. C. pseudonumbered. D. transformed.

dummy-coded

The search for patterns in your data is called: A. inferential statistical analysis. B. descriptive data analysis. C. exploratory data analysis.

exploratory data analysis

A set of mutually exclusive categories (classes) together with a count of the number of data values falling into each category is termed a: A. sorted list. B. cumulative distribution. C. frequency distribution. D. scatter plot.

frequency distribution.

Line graphs are appropriate when one wants to illustrate: A. the main effects of variables. B. categorical relationships among variables. C. dichotomized data splits. D. functional relationships between variables.

functional relationships between variables.

The best-fitting straight line on a scatter plot that minimizes the sum of the squared deviations of each data point from the line is called the: A. standard error line. B. optimal line. C. least-squares regression line. D. None of the answers is correct.

least-squares regression line.

With _____, you can estimate values of a variable based on knowledge of the values of others. A. linear regression B. the Pearson r C. the phi coefficient D. the coefficient of determination

linear regression

The presence of outliers can affect the _____ of the Pearson r. A. sign B. magnitude C. magnitude, sign, or both D. None of the answers is correct.

magnitude, sign, or both

Included in the five-number summary are the: A. minimum, the first quartile, the median, the third quartile, and the maximum. B. mean, the median, the mode, the standard deviation, and the interquartile range. C. minimum, the interquartile range, the standard deviation, the range, and the maximum. D. mean, the median, the interquartile range, the standard deviation, and the range.

minimum, the first quartile, the median, the third quartile, and the maximum.

When coding dependent variables, you should not worry about creating new variables or with making special categories because: A. computers cannot read such composite variables. B. they are rarely used in data analysis. C. most statistical analysis software have commands that lets one manipulate data in a variety of ways. D. All of the answers are correct.

most statistical analysis software have commands that lets one manipulate data in a variety of ways.

A curve that is steep at first but becomes progressively flatter as it moves along the x-axis is: A. negatively accelerated. B. positively accelerated. C. nonmonotonic. D. non-accelerated.

negatively accelerated.

By squaring the correlation coefficient, you can: A. determine how many deviant scores are there in your distributions. B. obtain the strength of the causal relationship between variables. C. obtain an index of the amount of variation in one variable that can be accounted for by variation in the other. D. determine how much unit change in X you can expect with a unit change in Y.

obtain an index of the amount of variation in one variable that can be accounted for by variation in the other.

The Spearman rank-order correlation is used when: A. dependent variables are scaled on a ratio scale. B. one variable being measured is on an interval scale and the other being measured is on a nominal scale. C. both of the variables being correlated are measured on a dichotomous scale. D. one wants to determine whether the relationship between variables is monotonic.

one wants to determine whether the relationship between variables is monotonic.

If your data are in the form of proportions or percentages, then a good type of graph to represent the value of each category in an analysis would be a: A. line graph. B. histogram. C. pie graph. D. bar graph.

pie graph

The measure of correlation to use when one variable is measured on an interval scale and the other is measured on a nominal scale is the: A. Spearman rank-order correlation. B. point-biserial correlation. C. phi coefficient. D. part correlation.

point-biserial correlation.

A(n) _____ curve is relatively flat at first and becomes progressively steep as it moves along the x-axis. A. negatively accelerated B. non-accelerated C. positively accelerated D. increasing

positively accelerated

A distribution is _____ if a long tail goes off to the right, upscale. A. normal B. positively skewed C. negatively skewed D. bimodal

positively skewed

Stemplots have the advantage over histograms of: A. plotting the shape of a distribution. B. preserving all the actual values present in the data. C. determining the center of a distribution. D. determining the spread of a distribution.

preserving all the actual values present in the data.

The _____ provides an estimate of the amount of error in prediction. A. standard deviation B. variance C. regression weight D. standard error of estimate

standard error of estimate

The mean is derived by: A. finding the most frequent score in a distribution. B. finding the middle score in an ordered distribution. C. summing the scores in a distribution and dividing the sum by the total number of scores. D. averaging the middle pair of scores in an ordered distribution.

summing the scores in a distribution and dividing the sum by the total number of scores.

A limitation of using grouped data is that: A. the average score may not represent the performance of individual subjects in a group. B. a curve resulting from plotting averaged data may not reflect the true nature of the psychological phenomenon being studied. C. grouping scores adds error variance to the data. D. the average score may not represent the performance of individual subjects in a group, and a curve resulting from plotting averaged data may not reflect the true nature of the psychological phenomenon being studied.

the average score may not represent the performance of individual subjects in a group, and a curve resulting from plotting averaged data may not reflect the true nature of the psychological phenomenon being studied.

If data are scaled on an interval or ratio scale, the mean becomes a less representative measure of center when: A. there are more than 10 scores in a distribution. B. there are less than 5 scores in a distribution. C. the mean and median are equal. D. the distribution of scores is strongly skewed.

the distribution of scores is strongly skewed.

When organizing data, a good strategy to adopt is: A. restrict yourself to looking at grouped data. B. restrict yourself to looking at individual data. C. to look at both grouped and individual data. D. to look at neither grouped nor individual data.

to look at both grouped and individual data.

For quantitative data (e.g., the number of milligrams of a drug), coding your data involves: A. dummy coding. B. transferring each subject's score to a computer coding sheet. C. assigning numeric values to categorical data. D. None of the answers is correct.

transferring each subject's score to a computer coding sheet.

Examining individual data shows how each subject performed in a study when: A. you have repeated measures of the same behavior. B. several subjects per treatment group provide data measured on an interval scale. C. more than five subjects are included in each treatment group. D. data are measured on a ratio scale.

you have repeated measures of the same behavior.

After entering data, _____. A. you need not check for data errors because the computer can do it for you B. the computer recognizes errors and corrects the data automatically C. you need not check for data errors because they are rare D. you should carefully check your data file for errors because the computer cannot detect incorrectly entered data

you should carefully check your data file for errors because the computer cannot detect incorrectly entered data