Question 1

In the context of controlling threats to internal validity in a study, there is a difference between random assignment and random selection. Which of the following statements is true regarding random assignment and random selection?
A)Assignment is how people are chosen.
B)Selection is what group people are placed in.
C)Selection is adding additional groups.
D)Selection is how people are chosen for a study.

Accepted Answer

Selection is how people are chosen and assignment is how they are placed in groups.

Question 2

What does cluster sampling refer to, in the context of increasing the external validity of a study?
A)It ensures proportional representation.
B)The sampling unit is a naturally occurring group.
C)It ensures a sample representative of the population.
D)Subjects do not know which group they are in.

Accepted Answer

Cluster sampling uses a naturally-occurring group as a study group. Using a group of coffee drinkers and a group of tea drinkers in a study is cluster sampling; this approach is often used in marketing research.

Question 3

In developmental research, variables are assessed as a function of time. How does cross-sectional design work?
A)Groups divided by age are assessed at the same time.
B)One group is studied at different points over a long period of time.
C)Representative samples of different age groups are assessed multiple times over a long period.
D)It combines longitudinal and cross-sequential design.

Accepted Answer

Different age groups are assessed at the same time in a cross-sectional design study. Specific factors that groups are compared on are independent variables, while time is not.

Question 4

Different research designs and strategies are used to gain specific types of information. How does correlational research work?
A)Investigators assign subjects to groups at random and they receive different levels of a variable.
B)Investigators can't infer causal relationships.
C)Variables are assessed as a function of time.
D)Investigators use naturally occurring groups.

Accepted Answer

Correlational research does not have internal validity, so no causal relationships can be determined. Causal relationships can be inferred in some instances. Correlational research can measure the strength of dependence between two variables that is not otherwise accounted for (causally, or by their response to other variables).

Question 5

When determining test construction, researchers consider number and type of variables, as well as ethical concerns. When would researchers choose to use multiple-baseline design?
A)When assignment is not possible
B)When reversal is not possible
C)When selection is not possible
D)When there is not enough data available

Accepted Answer

Multiple baseline design is used when reversal is not possible. This design addresses the ethical concerns of withholding a potentially-helpful treatment from a subject or withdrawing treatment that has proven to be helpful while the study is still underway.

Question 6

In qualitative research like case studies, theory is developed based on data and refines hypotheses. Which of the following statements about case studies is not correct?
A)They are used to measure attitude, preferences, and satisfaction.
B)They are based on the assumption that specific cases can be generalized.
C)They are based on close examination of one case.
D)They are most useful as pilot studies to identify variables to study using different methods.

Accepted Answer

Case studies are not used to measure attitude, preferences, and satisfaction, because those data are quantitative rather than qualitative. Surveys (which are quantitative research) are used to measure attitude, preferences, and satisfaction.

Question 7

There are three types of research design. A study comparing alcohol consumption rates between adolescent males and females is what type of research?
A)True experimental
B)Quasi-experimental
C)Observational
D)Non-manipulated

Accepted Answer

Observational, or non-experimental, research does not involve manipulation or intervention. This type of research studies independent variables (like gender) that cannot be manipulated combined with dependent variables that are not manipulated (alcohol consumption). Other types of research include more intervention.

Question 8

There are three main types of group design in research. Which design sometimes requires the process of counterbalancing?
A)Between groups design
B)Mixed design
C)Passive design
D)Within subjects design

Accepted Answer

Within subjects design refers to comparing groups that are related or correlated in some manner, such as from repeat measurements. Repeated measure design (one type of within subjects design) requires counterbalancing because of possible carryover effects between each measurement.

Question 9

There are three main types of group design in research. Which design involves groups that are both correlated and independent?
A)Between groups design
B)Mixed design
C)Repeated measure design
D)Within subjects design

Accepted Answer

Mixed design involves groups that are both correlated and independent; patients are assigned to different treatment groups (independent) and each group is measured more than once (correlated).

Question 10

Single-subject design in research studies one or a few subjects closely, rather than studying groups. What is one of the most common problems associated with single subject design?
A)Autocorrelation
B)Non-manipulation
C)Carryover effects
D)Cohort effects

Accepted Answer

Autocorrelation, which refers to the effect of measuring one individual repeatedly, is a significant problem in single-subject design. Autocorrelation is likely to produce scores that do not accurately reflect the research variables.

Question 11

Single-subject design in research studies one or a few subjects closely, rather than studying groups. Multiple baseline design resolves common problems associated with other single-subject designs, but has its own limitations. Which of the following is a problem associated with multiple baseline design?
A)Time investment
B)Ethical concerns
C)Threat of history
D)Failure of variable to return to baseline

Accepted Answer

Time and financial investment are problems associated with multiple baseline design. AB design carries the threat of history-it is hard to determine whether intervention or another event caused change. Ethical concerns and the failure of a dependent variable to return to baseline are both problems associated with ABAB design.

Question 12

Statistics is a method used to measure variables and analyze data. Statistical method has a scale of measurement and can be descriptive or inferential. In this method, what does ratio data refer to?
A)It divides variables into unordered categories.
B)It is scaled and at equal distances with no absolute zero.
C)It orders variables with no information about quantity.
D)It is interval data with an absolute zero.

Accepted Answer

Ratio data is interval data with an absolute zero; only data that can be multiplied or divided is used.

Question 13

Meta-analysis is used to study outcomes of psychotherapy and evaluate effectiveness of various therapeutic methods. What does meta-analysis utilize to draw conclusions about outcomes?
A)Available research literature
B)Feedback from therapists
C)Feedback from patients who have received therapy
D)Effect size of individual studies

Accepted Answer

Meta-analysis quantifies findings of multiple studies by applying empirical methods to available literature. Effect size is a result of meta-analysis. Meta-analysis is not part of a study itself, but uses the results of many studies.

Question 14

Meta-analysis is used to study outcomes of psychotherapy and evaluate effectiveness. In 1952, Hans Eysenck conducted one of the earliest meta-analysis on the improvement of neurotic disorders. What were his findings?
A)One-third of neurotics improved over a two-year period regardless of treatment
B)Two-thirds of neurotics improved over a two-year period regardless of treatment
C)Two-thirds of neurotics improved over a two-year period with treatment
D)One-half of neurotics improved over a one-year period without treatment

Accepted Answer

Eysenck reported in his study that two-thirds of neurotics improved over a two-year period with or without treatment. He also noted that treatment seemed to have a negative effect on improvement when compared to non-treatment.

Question 15

Meta-analysis is used to study outcomes of psychotherapy and evaluate effectiveness. What were the findings of a 1978 study of psychotherapy outcomes?
A)Spontaneous improvement rate is roughly 40%
B)Improvement with treatment rate is roughly 40%
C)Spontaneous improvement rate is roughly 60%
D)Both spontaneous improvement and improvement with treatment rates are roughly 60%

Accepted Answer

Bergin and Lambert, in their 1978 study, concluded that spontaneous improvement rate is close to 40%. More recent analysis has found similar rates of spontaneous improvement for various disorders.

Question 16

Frequency distribution provides a summary of a data set and indicates number of cases at any given score within a given range. Which of the following statements refers to skewed distribution?
A)It has asymmetrical frequency distributions.
B)It is known as the bell-shaped curve.
C)It is most often used for a high number of data points.
D)Half the data fall above the mean and half fall below it.

Accepted Answer

Skewed distribution has asymmetrical frequency distributions. In either a positively or negatively skewed data set, values are not evenly distributed on either side of the mean.

Question 17

In statistics, there are three ways to measure the central tendency in a data set: median, mean, and mode. Which of the following refers to the mode?
A)It is more useful for skewed distributions.
B)It is less sensitive to extreme values than the mean.
C)It is the most frequently occurring number.
D)It is sensitive to extreme values and skewed distributions.

Accepted Answer

The mode is the most frequently occurring number of a data set. There can be more than one mode; if 22 and 36 both occur an equal number of times (and more than any other number) they are both modes of that data set.

Question 18

In statistics, standard error of the mean refers to the expected error of a given sample mean. Which of the following statements is not true about standard error of the mean?
A)The score increases as N decreases.
B)It is the extent to which a sample mean can be expected to deviate from the corresponding population mean.
C)We know that one mean is greater or less than another mean.
D)The score can be expected to deviate +/- SE mean points from the population mean.

Accepted Answer

Standard error of the mean decreases as N increases.

Question 19

Squaring decimals is one of the basic mathematical principles used in statistics. What is the square of .3 (.3²)? A).09 B).9 C).006 D).06

Accepted Answer

.09 is the square of .3. When decimals are squared, the result is always smaller than the than the original number. When decimals expressed in tenths (like .3) are squared, the result is always expressed in hundredths (.09). For example .4 squared is .16 (simply square 4 and remember that the resulting value will be a smaller decimal and expressed in hundredths).

Question 20

Square-rooting decimals is one of the basic mathematical principles used in statistics. What is the square root of .64?
A).40
B).8
C).08
D).064

Accepted Answer

.8 is the square root of .64. when square-rooting a decimal, first express it in hundredths rather than in tenths-.5 becomes .50, .100 becomes .10. If there is not an exact square root of the decimal, look for the number that is closest, expressed in tenths. So, the square root of .50 is .7. 7x7=49, which is closest to 50.

Quiz 6: Research Methods and Statistics

In the context of controlling threats to internal validity in a study, there is a difference between random assignment and random selection. Which of the following statements is true regarding random assignment and random selection?

What does cluster sampling refer to, in the context of increasing the external validity of a study?

In developmental research, variables are assessed as a function of time. How does cross-sectional design work?

Different research designs and strategies are used to gain specific types of information. How does correlational research work?

When determining test construction, researchers consider number and type of variables, as well as ethical concerns. When would researchers choose to use multiple-baseline design?

In qualitative research like case studies, theory is developed based on data and refines hypotheses. Which of the following statements about case studies is not correct?

There are three types of research design. A study comparing alcohol consumption rates between adolescent males and females is what type of research?

There are three main types of group design in research. Which design sometimes requires the process of counterbalancing?

There are three main types of group design in research. Which design involves groups that are both correlated and independent?

Single-subject design in research studies one or a few subjects closely, rather than studying groups. What is one of the most common problems associated with single subject design?

Statistics is a method used to measure variables and analyze data. Statistical method has a scale of measurement and can be descriptive or inferential. In this method, what does ratio data refer to?

Meta-analysis is used to study outcomes of psychotherapy and evaluate effectiveness of various therapeutic methods. What does meta-analysis utilize to draw conclusions about outcomes?

Meta-analysis is used to study outcomes of psychotherapy and evaluate effectiveness. In 1952, Hans Eysenck conducted one of the earliest meta-analysis on the improvement of neurotic disorders. What were his findings?

Meta-analysis is used to study outcomes of psychotherapy and evaluate effectiveness. What were the findings of a 1978 study of psychotherapy outcomes?

Frequency distribution provides a summary of a data set and indicates number of cases at any given score within a given range. Which of the following statements refers to skewed distribution?

In statistics, there are three ways to measure the central tendency in a data set: median, mean, and mode. Which of the following refers to the mode?

In statistics, standard error of the mean refers to the expected error of a given sample mean. Which of the following statements is not true about standard error of the mean?

Squaring decimals is one of the basic mathematical principles used in statistics. What is the square of .3 (.3²) ?

Square-rooting decimals is one of the basic mathematical principles used in statistics. What is the square root of .64?