Inquizative 10 Exam 3

A recent study with 3,000 participants reported a fairly powerful negative correlation between the number of class absences by college students and their GPAs. According to recent guidelines for interpreting the magnitude of effect sizes, what r value was most likely to have been reported in this study?

- .30 This r best suits the description of negative and moderate in magnitude.

Identify the true statements about the strength and precision of correlations.

- All else being equal, the stronger an effect size is, the more accurate a future prediction based on that relationship will be. - The larger a sample size, the less likely it is that findings may have resulted from chance.

For her psychology class, Ezra is making a scatterplot of the digit spans (how many numbers you can remember and repeat back), with participants' memory for digits they read on the x-axis and participants' memory for digits they hear on the y-axis. The association is strong, but Ezra notices that one participant has a visual digit memory that is twice as long as anyone else's. What question about statistical validity is Ezra raising?

- Could outliers be affecting the relationship? One extreme score can have a strong effect on the correlation coefficient r.

Identify the false statements about the strength and precision of correlations.

- If a correlation is moderate in effect size, it is always statistically significant. - Effect size only gives information about the strength of a relationship and nothing else.

Identify the false statements about the validity of association claims.

- If an association claim is not generalizable, it should not be taken seriously. - An increased sample size increases the external validity of an association claim.

When is an outlier most likely to be problematic?

- Outliers have the larger influence on the correlation when the sample size is small and the outlier is extreme on both variables. - *when the sample size is small and the outlier is extreme on both variables

Identify the false statements about describing and analyzing associations.

- Scatterplots are often used to graph the relationship between a categorical variable and a quantitative variable. - Bar graphs show the data points for each participant.

Identify the true and false statements about this graph, which depicts the association between meeting location and marital satisfaction.

- This association would be best analyzed by looking at the difference in group averages. - This association involves one categorical and one quantitative variable. - Because meeting location is a categorical variable, looking at the difference in average marital satisfaction between online and offline meeting locations would be the best way to analyze this association. - Meeting location is a categorical variable, and marital satisfaction is a quantitative variable.

Professor Espejo wonders if there is an association between students' grades and extra credit points earned in his classes. He examines the number of extra credit points his students earned and the percentage grade his students earned without extra credit. He finds r = .28. Identify the true statements about Professor Espejo's study.

- This correlation tells him that students with higher grades are more likely to earn extra credit points than students with lower grades are. - A scatterplot is the best way for Professor Espejo to represent his results.

Professor Espejo wonders if there is an association between students' grades and extra credit points earned in his classes. He examines the number of extra credit points his students earned and the percentage grade his students earned without extra credit. He finds r = .28. Identify the false statements about Professor Espejo's study.

- This correlation tells him that students with lower grades are more likely than students with higher grades to earn extra credit points. - Professor Espejo's study involves one categorical and one quantitative variable.

Identify the true statements about correlations.

- To understand a correlation, you must consider both its strength and its direction. - An association claim is between measured variables.

Identify the true statements about describing and analyzing associations.

- When one of the variables in an association is categorical, researchers often analyze the difference between the means of the groups. - When both variables in a study are measured, it is a correlational study.

Identify the true statements about 95% confidence intervals.

- You can infer statistical significance from a 95% CI. - A 95% CI gives you information about the precision of the association. - A study with a small sample will have a wider 95% CI.

Identify the false statements about correlations.

- You can only examine correlations between two quantitative variables. - A bivariate correlation can involve an association between two or more variables.

A(n) ____ is an extreme data point that can often inaccurately alter an effect size. ___ __ __ occurs when all possible scores on a variable are not present, which can often inaccurately decrease an effect size. A(n) __ __ is when a set of data is not well represented by a straight line and can result in a zero effect size. All three of these issues can decrease ___ validity.

- outlier - restriction of range - curvilinear relationship - statistical

Mischel et al. (1972) studied delay of gratification in preschoolers. The researchers offered preschoolers a special reward if they could wait, or a less attractive treat if they chose not to wait. The researchers then conducted a follow-up study years later, studying the same preschoolers as adolescents. The researchers found a positive association between the preschoolers' waiting times and their self-control as adolescents. Identify the three causal criteria as established by Mischel's study.

- temporal precedence - covariance

What is an essential feature of studies that support association claims?

- the studies must involve a correlation between two measured variables - When both variables are measured, the claim being tested is an association claim.

Identify the false statements about 95% confidence intervals.

-A 95% CI gives you information about the strength of the association.

Vanessa is investigating the relationship between socioeconomic status and mental illness. She samples a group of low-income participants and finds that the relationship between her two variables is very weak. Vanessa plots her data on this scatterplot and does not see any obvious problems with it. What issue is most likely affecting Vanessa's results?

-Vanessa did not sample any participants with medium or high incomes, so the relationship her graph shows probably appears weaker than it really is. - RESTRICION OF RANGE

Identify the true statements about the validity of association claims.

A spurious association can occur when a third variable explains the association between two others.

Select the graph that shows a stronger effect size.

Because the points are more tightly packed, this graph shows a stronger effect size and would likely lead to a more accurate prediction.

Eliud wants to look at the association between age and satisfaction with life. He recruits a sample of elementary schoolchildren and finds that there is a zero correlation between age and satisfaction with life. Which graph depicts the potential statistical validity problem that exists in Eliud's study?

Eliud's statistical validity problem is restriction of range. He needs to look at people younger and older than elementary schoolchildren to get a full range of the variable of age.

correlation coefficient r,

Strength, or effect size, is represented by the value of the correlation coefficient r, while direction is represented by whether r is positive or negative.

Siva is investigating an association claim between political beliefs and age. His data show a correlation of r = .35. However, upon closer examination, Siva finds that the correlation is much stronger for men than it is for women. What type of variable is gender is this example?

The association between political beliefs and age depends on the variable gender, so gender is a moderator. Moderators add nuance to association claims without challenging their internal validity. - moderator

Chenoa finds a positive association between hours of sleep and well-being, and she wants to see whether this association is the same for teenagers (ages 16-19) as it is for young adults (ages 20-24). Which graph depicts a spurious association between hours of sleep and well-being?

Within each age group, there is no significant association between hours of sleep and well-being (the cloud of points does not slope in any direction for either group). It only appears that there is an association between hours of sleep and well-being because teenagers report more hours of sleep and higher well-being than young adults do overall. This means that the association between hours of sleep and well-being only exists because of a third variable, age group.

Do college students sleep fewer hours per day than high school students do?

bar graph

Is job title linked to salary?

bar graph

Is type of social media platform associated with feelings of jealously?

bar graph

Mischel et al. (1972) studied delay of gratification in preschoolers. The researchers offered preschoolers a special reward if they could wait, or a less attractive treat if they chose not to wait. The researchers then conducted a follow-up study years later, studying the same preschoolers as adolescents. The researchers found a positive association between the preschoolers' waiting times and their self-control as adolescents. Match each question to the type of validity it interrogates. How well was delay of gratification measured?

construct validity

Which two validities are the most important to establish for an association claim? Most Important - ? - ? Less Important internal validity external validity

construct validity statistical validity

In his second study, Dr. Kahue selects college students for a sample to examine the same question. He finds no relationship between BMI and depression. However, he notices that students with very low BMI and students with very high BMI had higher levels of depressed mood, but levels of depressed mood in students with moderate BMI were quite low. Dr. Kahue should be concerned with a ____ _____ in his second study.

curvilinear association

The term __ ___ describes the strength of an association between variables, and in correlations it is typically captured by a(n) __ . The precision of the correlation estimate is captured by a(n) ____ __.

effect size - r value - 95% CI

Mischel et al. (1972) studied delay of gratification in preschoolers. The researchers offered preschoolers a special reward if they could wait, or a less attractive treat if they chose not to wait. The researchers then conducted a follow-up study years later, studying the same preschoolers as adolescents. The researchers found a positive association between the preschoolers' waiting times and their self-control as adolescents. Match each question to the type of validity it interrogates. Can the results be generalized to all American children?

external validity

Mischel et al. (1972) studied delay of gratification in preschoolers. The researchers offered preschoolers a special reward if they could wait, or a less attractive treat if they chose not to wait. The researchers then conducted a follow-up study years later, studying the same preschoolers as adolescents. The researchers found a positive association between the preschoolers' waiting times and their self-control as adolescents. Identify the three causal criteria as not established by Mischel's study.

internal validity

Mischel et al. (1972) studied delay of gratification in preschoolers. The researchers offered preschoolers a special reward if they could wait, or a less attractive treat if they chose not to wait. The researchers then conducted a follow-up study years later, studying the same preschoolers as adolescents. The researchers found a positive association between the preschoolers' waiting times and their self-control as adolescents. Match each question to the type of validity it interrogates. Is there a third variable that explains this relationship?

internal validity

Bivariate correlations

involve an association between exactly two variables—no more.

Leonor recently collected survey data and was curious about the association claim between gender and symptoms of mental illness. She found the following correlation between the two variables: r = −.47, 95% CI [−.59, −.35]. Identify the terms as not applicable to this correlation.

moderate not statistically significant positive

Pengyu is interested in the association between the height of professional basketball players and their free-throw percentage. She finds a statistically significant negative association in the entire last season of the NBA. Looking at her scatterplot, Pengyu finds that one player is much shorter and has a much better free-throw percentage than the rest of the players. She also finds that the negative association only exists for less experienced NBA players, not for more experienced NBA players. Identify the issues as present in Pengyu's study.

moderator outlier

In association research, when the relationship between two variables changes depending on the level of a third variable, the third variable is called a(n) ___. This type of variable can help establish ____ ______

moderator --- external validity

Leonor recently collected survey data and was curious about the association claim between gender and symptoms of mental illness. She found the following correlation between the two variables: r = −.47, 95% CI [−.59, −.35]. Identify the terms as applicable to this correlation.

negative statistically significant categorical unusually large

Identify each correlation as either statistically significant or not statistically significant. r = .21, 95% CI [−.17, .59]

not statistically significant

Recently, researchers wanted to test the relationship between hours of exposure to violent video games and the number of real-life criminal behaviors. They found the following correlation between the two variables: r = .11, 95% CI [−.04, .26]. Identify the terms as applicable to this correlation.

not statistically significant positive weak- An effect size around .20 is typically considered moderate, while an effect size around .10 is typically considered weak.

Identify each correlation as either statistically significant or not statistically significant. r = −.45, 95% CI [−.92, .03]

not stats significant

Identify the associations as not statistically significant. The size of the effect (r) does not determine statistical significance, but we can infer statistical significance from the 95% CI.

r = −.41, 95% CI [−.85, .03] r = .25, 95% CI [−.15, .55] r = −.35, 95% CI [−.71, .01]

Identify the associations as statistically significant. The size of the effect (r) does not determine statistical significance, but we can infer statistical significance from the 95% CI.

r = −.42, 95% CI [−.20, −.64] r = .23, 95% CI [.03, .40] r = .65, 95% CI [.33, .97]

Dr. Kahue wants to examine the relationship between body mass index (BMI) and depression. In his first study, he selects American athletes who are currently training for the summer Olympic Games for his sample. Based on this sample, Dr. Kahue finds no relationship between BMI and depression. Dr. Kahue should be concerned with ____ _ ____ in his first study.

restriction of range

Is age associated with number of hours of sleep?

scatterplot

Is length of experience linked to salary?

scatterplot

Is time spent using social media associated with feelings of jealously?

scatterplot

Mischel et al. (1972) studied delay of gratification in preschoolers. The researchers offered preschoolers a special reward if they could wait, or a less attractive treat if they chose not to wait. The researchers then conducted a follow-up study years later, studying the same preschoolers as adolescents. The researchers found a positive association between the preschoolers' waiting times and their self-control as adolescents. Match each question to the type of validity it interrogates. Has this association been replicated?

statistical validity

Recently, researchers wanted to test the relationship between hours of exposure to violent video games and the number of real-life criminal behaviors. They found the following correlation between the two variables: r = .11, 95% CI [−.04, .26]. Identify the terms as not applicable to this correlation.

statistically significant categorical moderate negative

Identify each correlation as either statistically significant or not statistically significant. r = .10, 95% CI [.05, .15]

stats significant

Identify each correlation as either statistically significant or not statistically significant. r = −.23, 95% CI [−.33, −.13]

stats significant

Pengyu is interested in the association between the height of professional basketball players and their free-throw percentage. She finds a statistically significant negative association in the entire last season of the NBA. Looking at her scatterplot, Pengyu finds that one player is much shorter and has a much better free-throw percentage than the rest of the players. She also finds that the negative association only exists for less experienced NBA players, not for more experienced NBA players. Identify the issues as not present in Pengyu's study.

third-variable problem restriction of range

An association claim with ___ variables can be examined with a ____ correlation, and the results of the test have two primary components. The first component tells you whether the association is positive or negative; it is referred to as _____. The second component tells you how closely the variables are associated; it is referred to as ____.

two, bivariate, direction, strength