Research Methods Exam 2
Which of the following claims is an association claim? a. Teenage pot smoking affects intelligence. b. Depression in the elderly may predict dementia. c. Tanning changes the brain. d. A thoughtful gift makes the giver feel closer to the recipient.
*b. Depression in the elderly may predict dementia*
Which validities are important for a frequency claim?
1. *Construct* is most important for frequency claim because if we don't have an appropriately operationalized construct we don't have the ability to make any claim at all 2. External-> important to pay attention to, BUT may not be generalizable - Has to do with type of claim being made EX: SOMA system at Mizzou 3. Statistical-> look at descriptive statistics (frequency of variable and who it affect, NOT comparing 2 groups) EX: 87% of women in the U.S. Smoke- Look at "margin of error" - A stat will say "87 +/-3%"-> Margin of Error
4 Types of Validity
1. Construct 2. External 3. Statistical 4. Internal
3 Types of Claims
1. Frequency 2. Association 3. Causal
2 ways a bivariate correlation can be presented
1. Scatterplot (both quantitative) 2. Bar Graph (one is categorical)
EX of how a multiple regression study is done- whites have longer lives because it is possibly due to the fact that they have more access to better healthcare
1. Use a bar graph 2. Look at confounds- where you grow up, access to green space 3. Then look at to say whites live 4 years longer than blacks, *we cannot establish and use this as a claim because we do not yet have a pattern established* - We would need to do more studies on this subject to come to that conclusion, one study is NOT enough
Spurious Association
A bivariate association that is attributable only to systematic mean differences on subgroups within the sample - the original association is not present within the subgroups
Association Claim
A claim about two variables, in which the value of one variable is said to vary systematically with the value of another variable - records a correlation - correlation does not mean causation EX: "Women who smoke have increased scores on depression"
Causal Claim
A claim arguing that a specific change in one variable is responsible for influencing the value of another variable
Frequency Claim
A claim that describes a particular rate or degree of a SINGLE variable EX: "75% of women smoke"- smoke is the variable
Statistical Significance
A researcher's assessment of whether a result from a sample could have come from a population in which there is no association or no difference
Conceptual Definition
A researcher's definition of a variable at the theoretical level
Margin of Error of the Estimate
A statistic indicating the probable true value of a percentage estimate in the population - based on sample size
multiple regression
A statistical technique that computes the relationship between a predictor variable and a criterion variable, controlling for other predictor variables - You are taking into account as many confounds as you think are valuable to evaluate
t Test
A statistical test used to evaluate the size and significance of the difference between two means
multivariate design
A study designed to test an association involving more than two measured variables
Experiment
A study in which one variable is manipulated and the other is measured
Measure Variable
A variable in a study whose levels are observed and recorded
predictor variable
A variable in multiple-regression analysis that is used to explain variance in the criterion variable. - (independent variable) - all of the things that we need to "control for" go into our multiple regressions
mediator (mediating variable)
A variable that helps explain the relationship between two other variables
Curvilinear Association
An association between two variables which is not a straight line - as one variable increases, the level of the other variable increases and then decreases - U-shaped
Bivariate correlation
An association that involves exactly two variables - correlational studies
Constant
An attribute that could potentially vary but that has *only one level in the study in question*
Variable
An attribute that varies, having at least two levels
Construct Validity
An indication of how well a variable was measured or manipulated in a study
External Validity
An indication of how well the results of a study generalize to individuals besides those in the study itself
"control for"
Holding a potential third variable at a constant level while investigating the association between two other variables
Level
One of the possible variations of a variable
What does it mean when a sample's result is extreme?
That the result would rarely be found in such a population and is said to be statistically significant
Restriction of Range
The absence of a full range of possible scores on one of the variables, so *the relationship from the sample underestimates the true correlation*
Validity
The appropriateness of a conclusion or decision
parsimony
The degree to which a theory provides the simplest explanation of some phenomenon - the best explanation that requires making the fewest exceptions or qualifications - If we run multiple regression longitudinal studies do we establish good results that are parsimonious (simplest explanation) EX: Health sciences→ established smoking lead to lung cancer Did lots of multiple regression longitudinal studies- plug all predictor variable to test for criterion variable and see if there is an association
Covariance
The degree to which two variables go together
Generalizability
The extent to which the subjects in a study represent the populations they are intended to represent - how well the settings in a study represent other settings
Effect size
The magnitude, or strength, of a relationship between two or more variables
Directionality Problem
The occurrence of both variables being measured around the same time, making it unclear which variable in the association came first - (correlational study) - temporal precedence
Temporal Precedence
The proposed causal variable comes first in time, before the proposed outcome variable
Operational Definition
The specific way in which a concept of interest is measured or manipulated as a variable in a study
criterion variable
The variable in a multiple-regression analysis that the researchers are most interested in understanding or predicting - (dependent variable)
Which of the following questions addresses construct validity? a. How well has the researcher measured or manipulated the variables in the study? b. What is the effect size? c. To what populations, settings, and times can we generalize this claim? d. Does the study control for alternative explanations?
a. How well has the researcher measured or manipulated the variables in the study?
Mischel (1972) studied delay of gratification in preschoolers: Children were offered a special reward if they could wait or a less attractive treat if they chose not to wait. A follow-up study was done years later, looking at the same children as adolescents. The researchers found an association between the waiting times of the preschoolers and parents' reports of the same children's behaviors as adolescents. Which of the following is a question one could ask to assess the construct validity of this association? a. How well was delay of gratification measured? b. Can the results be generalized to all American children? c. Were the results statistically significant? d. Is there a third variable that explains this relationship?
a. How well was delay of gratification measured?
Multiple-regression designs help address internal validity in which of the following ways? a. by ruling out third variables b. by establishing temporal precedence c. by eliminating selection threats d. by introducing a control condition
a. by ruling out third variables
What kind of a claim is the following headline making? "You Gotta Have Friends? Most Have Just Two True Pals." a. frequency claim b. association claim c. causal claim d. anecdotal claim
a. frequency claim
Dr. Samuels does a study that finds children with unusual names are more likely to have delinquency records as adolescents because they were teased more, and the teasing makes them act out. In the relationship between having an unusual name and adolescent delinquency, Dr. Samuels found that teasing plays which of the following roles? a. mediator b. moderator c. confounding third variable d. criterion variable
a. mediator
Professor Fofana wonders if there is an association between students' grades and extra credit points earned in his classes. He makes a scatterplot, with the number of extra credit points earned on the x-axis and the numerical grade in his course without extra credit on the y-axis. He finds r = .28. In addition to this correlation coefficient, which of the following would Professor Fofana need to determine if this result is statistically significant? a. the sample size b. the mean of the scores c. the effect size d. the range of responses
a. the sample size
There is a strong positive association between years of education and income. The mean income for American adults in 2005 was $32,000 and the average number of years of education was 12. If Mr. Lopez has 16 years of education, which would you predict about his income? a. The best estimate would be the mean income of $32,000. b. His income is probably higher than $32,000. c. His income is probably lower than $32,000. d. There isn't enough information to make a prediction.
b. His income is probably higher than $32,000.
Professor Fofana wonders if there is an association between students' grades and extra credit points earned in his classes. He makes a scatterplot, with the number of extra credit points earned on the x-axis and the numerical grade in his course without extra credit on the y-axis. He finds r = .28 and p < .001. Which of the following correctly explains what this means? a. The result probably came from a zero-association population. b. It is very unlikely this association was found in the sample when, in the full population, there is really no association. c. The result is not statistically significant. d. There is probably no association between extra credit and course grades in the full population.
b. It is very unlikely this association was found in the sample when, in the full population, there is really no association.
Dr. Stevens wants to examine the relationship between body mass index (BMI) and depression. He selects as his research subjects a sample of American athletes who are currently training for the summer Olympic Games. Dr. Stevens finds no relationship between BMI and depression. Which of the following is one problem with his research design that could have kept him from finding a relationship between those variables? a. There is a third-variable problem. b. There is a restriction-of-range problem. c. There is a problem with outliers in his sample. d. There is a directionality problem.
b. There is a restriction-of-range problem
It has been reported that half of Americans show road rage. For this claim to have strong external validity, which of the following would have been the best sample for the researcher to have used? a. students from Intro to Psych courses who are earning extra credit b. a cross-section of American drivers representing men and women; people from the city, suburbs, and farms; and people of all ages c. young men from ages 20 to 30 years; because they are the group most frequently charged with road rage, they should be the focus d. a random sample of people from a Los Angeles telephone book
b. a cross-section of American drivers representing men and women; people from the city, suburbs, and farms; and people of all ages
Which of the following is an operational definition of stress? a. feelings of anxiousness and pressure b. a measurement of the amount of a "fight or flight" hormone in saliva c. mental tension d. worry about school
b. a measurement of the amount of a "fight or flight" hormone in saliva
If the relationship between two variables changes depending on the level of another variable c, which of the following is the term for this other variable, c? a. a third-variable problem b. a moderator c. a mediator d. a confound
b. a moderator
Heather reads an article entitled, "Waist Circumference Associated with Life Expectancy." She wants to use the correlation reported in the article to predict her own life expectancy based on her waist circumference. What kind of correlation would allow her to make the most accurate prediction? a. a zero correlation b. a strong positive correlation c. a weak positive correlation d. a weak negative correlation
b. a strong positive correlation
What kind of a claim is the following headline making? "Former NFLers at Higher Risk for Brain, Mood Problems." a. frequency claim b. association claim c. causal claim d. anecdotal claim
b. association claim
Which type of research design involves measuring the same variables, for the same people, across different points in time? a. cross-sectional b. longitudinal c. pattern and parsimony d. multiple regression
b. longitudinal
Dr. Aarons does a study that finds having a cognitively demanding job is associated with cognitive benefits in later years, but only among men, not among women. In her findings, in the relationship between having a cognitively demanding job and cognitive benefits later in life, sex plays which of the following roles? a. mediator b. moderator c. confounding third variable d. criterion variable
b. moderator
When a relationship between two variables depends on the level of a third variable, that kind of a third variable is called a _____. a. mediator b. moderator c. spurious correlation d. predictor variable
b. moderator
Which type of study design is used when researchers investigate causality by using a variety of correlational studies that all point in a single, causal direction? a. longitudinal study b. pattern and parsimony c. multiple-regression design d. cross-lag design
b. pattern and parsimony
Mischel (1972) studied delay of gratification in preschoolers: Children were offered a special reward if they could wait or a less attractive treat if they chose not to wait. A follow-up study was done years later, looking at the same children as adolescents. The researchers found an association between the waiting times of the preschoolers and parents' reports of the same children's behaviors as adolescents. Overall, a positive relationship between waiting time as a preschooler and self-control in adolescence emerged. Which correctly answers whether a causal relationship can be inferred? a. No, because covariance was not established. b. No, because temporal precedence was not established. c. No, because internal validity was not established. d. Yes, because covariance, temporal precedence, and internal validity were established.
c. No, because internal validity was not established.
June is interested in looking at whether social media use predicts feelings of loneliness and found there was a positive relationship between the two variables. However, she finds that after controlling for the amount of time a person spends with friends per week, social media use was no longer associated with feelings of loneliness. Which of the following is the correct interpretation of this finding? a. The amount of time spent with friends is not associated with social media use. b. The beta for amount of time spent with friends is significant. c. The amount of time spent with friends is a third-variable problem. d. The amount of time spent with friends predicts social media use.
c. The amount of time spent with friends is a third-variable problem.
A multiple-regression analysis is run to examine third variables as a follow-up to the study indicating that boys with unusual names are more likely to commit crimes. Unusual names, ethnic backgrounds, and geographical regions are all included as predictor variables. Even after controlling for all these variables, unusual names still predict criminal activity. Which of the following explains why this study doesn't establish causation? a. Temporal precedence isn't established between the variables. b. The beta values are not shown, so there isn't enough information to establish covariance. c. There may be some other third variable. d. No significant cross-lag correlations were found.
c. There may be some other third variable.
Dr. Russell did a study that found praise provided by supervisors is associated with higher levels of work productivity only because more-motivated employees are praised more often, and highly motivated people are more productive. In her findings, employee motivation is a ___________ in the relationship between praise from supervisors and work productivity. a. mediator b. moderator c. confounding third variable d. criterion variable
c. confounding third variable
Dr. Stevens did a study that found having a cognitively demanding job is associated with cognitive benefits in later years because people who are highly educated take cognitively demanding jobs, and people who are highly educated have better cognitive skills. In the relationship between having demanding job and cognitive benefits in later years, she found that the amount of education plays which of the following roles? a. mediator b. moderator c. confounding third variable d. criterion variable
c. confounding third variable
Vida is studying the connection between school grades and time spent using social media. She finds a strong correlation, showing students with lower grades spend more time using social media. She decides that before she can claim increased use of social media causes grades to drop, she must make sure the social media came before the low grades. Which criterion of causality is she concerned with? a. covariance b. statistical significance c. temporal precedence d. internal validity
c. temporal precedence
Which of the answer pairs correctly completes the following sentence: Although we cannot establish causation with correlational designs, longitudinal designs address concerns of _____ and multiple regression addresses concerns of ____? a. internal validity; covariance b. internal validity; temporal precedence c. temporal precedence; internal validity d. temporal precedence; covariance
c. temporal precedence; internal validity
Reading the news on the Internet, Johan comes across the headline, "When Stress is Increased, Men Rush Ahead, Women More Cautious." (This headline is based on a study conducted by Lighthall et al., 2011.) In this study, men and women were asked to perform a decision task as many times as possible in a set period, in either a stressed or unstressed condition. In the unstressed condition, men and women performed similarly. However, in the stressed condition, the number of decision tasks performed by men increased while the number performed by women decreased. Which of the following is a variable in this study? a. the decision task type b. the length of the set period c. the amount of stress d. the cause of the stress
c. the amount of stress
When is an outlier most likely to be problematic? a. when the sample size is large and the outlier is extreme on both variables b. when the sample size is small and the outlier is extreme on one of the variables c. when the sample size is small and the outlier is extreme on both variables d. when the sample size is large and the outlier is extreme on one of the variables
c. when the sample size is small and the outlier is extreme on both variables
Which of the following phrases in a popular media article suggests that multiple regression was used? a. "made a difference in" b. "depends on" c. "is more likely than" d. "controlled for"
d. "controlled for"
Nesta is making a scatterplot of the digit spans (how many numbers you can remember and repeat back) for his psychology class, with the memory for digits the students hear on one axis and the memory for digits the students read on the other. The association is strong, but he notices one student has a visual digit memory that is twice as long as anyone else. Which statistical validity question is he raising? a. Is the correlation statistically significant? b. Is there a restriction of range? c. Is the relationship curvilinear? d. Could outliers be affecting the relationship?
d. Could outliers be affecting the relationship?
Michelle found a positive association between hours of sleeping and well-being. She looked to see whether this association was the same for teenagers (ages 16-19) and young adults (ages 20-24). Which of the following would most likely suggest this association between hours of sleep and well-being is a spurious association? a. The association between hours of sleep and well-being is stronger for teenagers than young adults. b. The association between hours of sleep and well-being are both equally positively associated for teenagers and young adults. c. Hours of sleep and well-being are positively associated for teenagers but have a zero association for young adults. d. Hours of sleep and well-being are positively associated because, overall, teenagers report sleeping more and having greater well-being than young adults.
d. Hours of sleep and well-being are positively associated because, overall, teenagers report sleeping more and having greater well-being than young adults.
Jenny reads the headline, "Tea Party Supporters Have Slipped To 20 Percent." She asks, "What is the margin of error of the estimate?" What validity is she interrogating? a. construct validity b. internal validity c. external validity d. statistical validity
d. statistical validity
Mischel (1972) studied delay of gratification in preschoolers: Children were offered a special reward if they could wait or a less attractive treat if they chose not to wait. A follow-up study was done years later, looking at the same children as adolescents. The researchers found an association between the waiting times of the preschoolers and parents' reports of the same children's behaviors as adolescents. The parents' ratings of likelihood of yielding to temptation correlated with the preschool waiting time measurement at r = −.50. Which describes this effect size according to Cohen's benchmarks? a. zero b. weak c. moderate d. strong
d. strong
What is the name for the measured variable in an experiment? a. the constant b. the testing variable c. the independent variable d. the dependent variable
d. the dependent variable
Beta
similar to an r value BUT for a multiple regression
Which validities are important for an association claim?
1. Construct & External (still... obviously- similar reasons as before) 2. Statistical→ now becomes more complicated - Type 1 Error & Type 2 Error: - P-Value < 0.05 → if we set our p value to .05, we only will accept a 5% percent chance OR LESS of finding a difference when there is no difference - We set the threshold for the likelihood we get a type 1 error - "Statistically significant difference"- *statistical significance does NOT equal clinical significant* EX: Comparing smoking and depression
Which validities are important for a causal claim?
1. Construct & External (still...) 2. Statistical (same as association) Requirements for causality... - *Covariance*: some sort of correlation between the two variables - *Temporal Precedence*: the thing that causes the thing has to come first - *Internal Validity*- is there any reason that any other confound could have come in and caused this change?
Correlational Study
A study that includes two or more variables, in which all of the variables are measured - can support an association claim
Internal Validity
A study's ability to rule out alternative explanations for a causal relationship between two variables - *Only* for causal claims - looks at alternative explanations
Manipulated Variable
A variable in an experiment that a researcher controls - i.e. assigning participants to different levels
Construct
A variable of interest defined as part of a formal statement of a psychological theory - at an abstract level
Conceptual Variable
A variable of interest stated conversationally - at an abstract level
Moderator
A variable that, depending on its level, changes the relationship between two other variables
What is the difference between internal VALIDITY and internal RELIABILITY?
Internal Validity- have we taken into account all of the variables that could affect our claim Vs. Internal Reliability→ All the questions go together
Statistical Validity
The extent to which statistical conclusions derived from a study are accurate and reasonable
Third-variable problem
The existence of a plausible alternative explanation for the association between two variables - (correlational study) - internal validity
Operationalize
To turn a conceptual definition into a specific measured/manipulated variable in order to conduct a research study
Correlate
Two or more variable to occur or vary together systematically
Type II Error ("Miss")
When researchers conclude that their study has not detected an effect in a population, when there really is one
Type I Error ("False Positive")
When researchers conclude that there is an effect in a population, when there really is none
Which of the following is an example of a causal claim? a. Ice applied to a twisted ankle prevents swelling. b. Women regift at a 50% greater rate than men. c. Sweetened drinks are linked to depression risk. d. Folic acid is tied to better toddler talk.
a. Ice applied to a twisted ankle prevents swelling.
In most experiments, tradeoffs are made between validities because it is not possible to achieve all four at once. What is the most common tradeoff? a. Increased internal validity results in decreased external validity. b. Increased construct validity results in decreased statistical validity. c. Increased statistical validity results in decreased internal validity. d. Increased external validity results in decreased statistical validity.
a. Increased internal validity results in decreased external validity.
Which of the following is an essential feature of studies that support association claims? a. They involve two measured variables. b. They involve a correlation between 0 and 1. c. They involve a correlation between one quantitative variable and one categorical variable. d. They involve a correlation between one measured variable and one manipulated variable.
a. They involve two measured variables.
Dr. Thompson researches gang-related crime in a large city. She notices more graffiti appears when there are more ice cream trucks in town. She does a study that measures the frequency of new graffiti being reported and ice cream truck sales for each week over a year. She finds a positive association between ice cream truck sales and graffiti and concludes the ice cream trucks are encouraging graffiti. Her colleague, Dr. Richardson, points out that both ice cream sales and graffiti might be influenced by rising temperatures during the summer. Which kind of problem has Dr. Richardson identified? a. a third-variable problem b. a restriction-of-range problem c. a problem with outliers in the sample d. a moderation problem
a. a third-variable problem
What are the three criteria that are required for a causal claim? a. covariance, temporal precedence, and internal validity b. zero correlation, statistical validity, and internal validity c. zero correlation, temporal precedence, and external validity d. covariance, statistical validity, and external validity
a. covariance, temporal precedence, and internal validity
Which type of validity is important to interrogate for causal claims, but not association claims? a. internal validity b. external validity c. construct validity d. statistical validity
a. internal validity
Reading the news on the Internet, Johan comes across the headline, "When Stress is Increased, Men Rush Ahead, Women More Cautious." (This headline is based on a study conducted by Lighthall et al., 2011.) In this study, men and women were asked to perform a decision task as many times as possible in a set period, in either a stressed or unstressed condition. In the unstressed condition, men and women performed similarly. However, in the stressed condition, the number of decision tasks performed by men increased while the number performed by women decreased. Which of the following is a constant in this study? a. the amount of time to perform the decision task b. sex of the participants c. the amount of stress d. number of decision tasks performed
a. the amount of time to perform the decision task
Professor Nakum designs a memory experiment to test the effect of word familiarity on memory. Three lists of words are created: common words, uncommon words, and made-up words. Participants study one of the lists of 30 words for 5 minutes, do math problems for 5 minutes, then write all the words they recall from the list. Their score is the number of words correctly recalled. Which of the following is the independent variable in this study? a. the type of word list b. the time spent studying the list c. the length of the list studied d. the number of words correctly recalled
a. the type of word list
Phuong is conducting an experiment on proofreading. All participants are asked to read a passage with several typos and correct the errors. However, one group proofreads by reading silently, a second group proofreads by reading aloud, and a third group proofreads by reading the passage silently backward. The researcher calculates the average number of errors found in each group and finds that both the reading silently and reading aloud groups found more errors than the reading silently backward group. What are the variables in this study? a. type of proofreading and number of errors found b. reading silently, reading aloud, or reading silently backward c. the reading skill of the participant d. reading forward and reading backward
a. type of proofreading and number of errors found
longitudinal study
asking the same questions, to the same people, multiple times EX: we are wanting to explore diet and depression, we go out and ask a whole bunch of people to answer a questionnaire. 6 months later we get ahold of those same people and ask them those questions again
The Yerkes-Dodson law (1908) shows performance increases with arousal up to a point, but beyond that, performance decreases with increasing arousal. Which type of correlation is this? a. zero b. curvilinear c. positive d. negative
b. curvilinear
Vida is studying the connection between school grades and time spent using social media. She measures social media use at the beginning of the semester and grades at the end of the semester. Vida finds using more social media early in the semester was linked with lower school grades. Which other criterion of causality does she need if she wants to establish causation? a. convergent validity b. internal validity c. temporal precedence d. covariance
b. internal validity
Professor Fofana wonders if there is an association between students' grades and whether they complete extra credit in his classes. He makes a scatterplot, with the number of extra credit points earned on the x-axis and the numerical grade in his course without extra credit on the y-axis. He finds r = .28. According to Cohen's conventions, how strong is this association? a. small, or weak b. medium, or moderate c. large, or strong d. not significant
b. medium, or moderate
Professor Lee is curious if there is any pattern to who earns extra credit in her course. She examines this question by graphing a scatterplot of her students' exam grades and the number of extra credit points earned. She finds that the students with the lowest exam grades tend to have the most extra credit points. What type of association is this? a. zero b. negative c. positive d. causal
b. negative
Jenna is interested in the association between the height of professional basketball players and their free-throw shooting percentage. She looks at the correlation between NBA players and their free-throw percentage from last season and she finds a statistically significant negative association. Jenna's friend Elizabeth suggests Jenna should look at a scatterplot of the data. Jenna follows Elizabeth's advice and finds one of the players is much shorter than the rest of the players and that player has a much better free-throw shooting percentage. When Jenna removes this player from her analysis, she finds there is no longer a statistically significant relationship between height and free-throw shooting. Which kind of problem has Elizabeth helped Jenna identify? a. a third-variable problem b. a restriction-of-range problem c. a problem with an outlier in the sample d. a moderation problem
c. a problem with an outlier in the sample
Which of the following variable or variables is manipulated, rather than measured? a. # of pair of shoes owned b. a person's height c. amount of aspirin a researcher gives a person to take d. degree of happiness (rated on scale 1-10) e. type of praise a researcher uses in groups of dogs (verbal or treat)
c. amount of aspirin a researcher gives a person to take d. degree of happiness (rated on scale 1-10)
Professor Schwartz examines the relationship between time spent at a shopping mall and happiness. She finds that for millennials, the more time in the mall is associated with higher levels of happiness. She finds that for baby boomers, the more time in the mall is associated with lower levels of happiness. Which is the moderator in this relationship? a. level of happiness b. time spent in the mall c. generation of the people being examined d. the relationship between happiness and mall time
c. generation of the people being examined
Professor Nakum designs a memory experiment to test the effect of word familiarity on memory. Three lists of words are created: common words, uncommon words, and made-up words. Participants are randomly assigned to study one of the lists of 30 words for 5 minutes, do math problems for 5 minutes, then write all the words they recall from the list. Their score is the number of words correctly recalled. The use of random assignment of participants increases which of the following? a. the temporal precedence of the study b. the strength of association of the study c. internal validity of the study d. external validity of the study
c. internal validity of the study
Researchers de Abreu, Gathercole, and Martin (2011) found the correlation of nonword repetition and digit recall in a memory was r = .59. Based on Cohen's (1992) guidelines, which of the following describes this effect size? a. small b. medium c. large d. More information is needed to make this determination.
c. large
In addition to effect size, you must also know which of the following to determine if a correlation is statistically significant? a. direction of the association b. scale of the scatterplot c. sample size d. external validity
c. sample size
Marvin reads a journalistic report of a research study and asks, "How strong was the effect?" Which validity is Marvin asking about? a. internal validity b. external validity c. statistical validity d. construct validity
c. statistical validity
For an association claim, you interrogate the following validities: a. statistical, internal, and construct b. external, statistical, and internal c. statistical, construct, and external d. construct, internal, and external
c. statistical, construct, and external
Professor Fofana wonders if there is an association between students' grades and extra credit points earned in his classes. He first made a scatterplot, with the number of extra credit points earned on the x-axis and the numerical grade in his course without extra credit on the y-axis. He then decides the plot would be clearer if he converted the numerical grades into passing or failing the course, so he plots a bar graph with pass/fail on the x-axis and the mean number of extra credit points earned on the y-axis. Which type of statistic would he run to determine if there is a relationship between pass/fail and extra credit points earned? a. bivariate correlation b. mean c. t test d. Cronbach's alpha
c. t test
To look at the relationship between reaction time and level of expertise in tennis, experts and nonexperts in tennis were compared. Which of the following would be the most appropriate, easiest way to evaluate the relationship between these variables? a. correlation coefficient and a scatterplot b. Cronbach's alpha and a bar graph c. t test and a bar graph d. correlation coefficient and a bar graph
c. t test and a bar graph
Professor Nakum designs a memory experiment to test the effect of word familiarity on memory. Three lists of words are created: common words, uncommon words, and made-up words. Participants study one of the lists of 30 words for 5 minutes, do math problems for 5 minutes, then write all the words they recall from the list. Their score is the number of words correctly recalled. How were the words for each list selected? a. to operationalize different levels of the independent variable "difficulty" b. to operationalize different levels of the dependent variable "memory" c. to operationalize different levels of the independent variable "familiarity" d. to confuse participants
c. to operationalize different levels of the independent variable "familiarity"
Professor Fofana wonders if there is an association between students' grades and extra credit points earned in his classes. He makes a scatterplot, with the number of extra credit points earned on the x-axis and the numerical grade in his course without extra credit on the y-axis. He finds r = .28. What does this correlation tell him about which students take advantage of the extra credit option? a. Students with higher grades are less likely than students with lower grades to do extra credit work. b. Students with lower grades are more likely than students with higher grades to do extra credit work. c. All students are equally likely to do extra credit work. Correct! d. Students with higher grades are more likely than students with lower grades to do extra credit work.
d. Students with higher grades are more likely than students with lower grades to do extra credit work.
There is a negative association between exercise and obesity. Which of the following would a researcher need to demonstrate to make the claim that a lack of exercise causes obesity? a. There is a positive relationship between exercise and being thin. b. There are no obese people who exercise. c. The association between exercise and obesity generalizes to the whole population. d. The lack of exercise came before the obesity.
d. The lack of exercise came before the obesity.
Reading the news on the Internet, Johan comes across the headline, "When Stress is Increased, Men Rush Ahead, Women More Cautious." (This headline is based on a study conducted by Lighthall et al., 2011.) In this study, men and women were asked to perform a decision task as many times as possible in a set period, in either a stressed or unstressed condition. In the unstressed condition, men and women performed similarly. However, in the stressed condition, the number of decision tasks performed by men increased while the number performed by women decreased. In this study, the number of decision tasks performed is best described as which of the following? a. a constant b. a level of a variable c. a manipulated variable d. a measured variable
d. a measured variable
A recent headline read, "School Lunches Make Kids Fat." The article cited a study comparing children at two schools. The school with the lower obesity rate only had a few children who ate lunch provided by the school. The other school had a greater percentage of obese children and most of these children ate school lunches. No mention was made that many of the children who eat school lunches are low-income children who receive free lunches. Poverty is a major factor in obesity. Which validity is threatened by the potential confound, poverty? a. construct validity b. statistical validity c. external validity d. internal validity
d. internal validity
Professor Nakum designs a memory experiment to test the effect of word familiarity on memory. Three lists of words are created: common words, uncommon words, and made-up words. Participants study one of the lists of 30 words for 5 minutes, do math problems for 5 minutes, then write all the words they recall from the list. Their score is the number of words correctly recalled. Which of the following is the dependent variable in this study? a. the type of word list b. the time spent studying the list c. the length of the list studied d. the number of words correctly recalled
d. the number of words correctly recalled
