Question 1

Which of the following would tell us the percentage of variance in one variable that can be accounted for by knowing the other variable?

Accepted Answer

The correct choice is “r x r” also known as the coefficient of determination. This is calculated by squaring the correlation coefficient (r) between the two variables. The resulting value represents the percentage of variance in one variable that can be explained by knowing the other variable. Therefore, by choosing option C, we get the percentage of variance in one variable that can be accounted for by knowing the other variable.

Question 2

Wendy has determined that the correlation between her reading screening test and her students' reading grades is .30.What percent of the variation in reading scores is accounted for by knowing the students' scores on the
Screening test?

Accepted Answer

The percentage of variation accounted for by the correlation is found by squaring the correlation coefficient (r) and converting it to a percentage. Here, r = 0.30, so r^2 = 0.09, which is 9%.

Question 3

If there is a correlation of .78 between socioeconomic status and IQ score,which of the following statements is TRUE?

Accepted Answer

The answer of If there is a correlation of .78...

Question 4

If the correlation between anxiety and test scores is -.85,then we can safely conclude that

Accepted Answer

The correlation coefficient of -.85 indicates a negative relationship between anxiety and test scores, meaning as anxiety levels increase, test performance decreases. Therefore, choices A and B can be ruled out. Choice C is also incorrect as it suggests a positive relationship between anxiety and test scores.

Question 5

If there is a .75 correlation between the hours that students devote to studying and their grades

Accepted Answer

Correlation does not necessarily indicate causation. There may be other factors, such as motivation and interest in the subject, that are influencing both the amount of studying and the grades earned. Therefore, it is not appropriate to conclude that the correlation alone indicates a direct causal relationship.

Question 6

For a correlation of +1.00 or -1.00,what percent of the variation in the Y measure is accounted for by knowing the X measure?

Accepted Answer

A correlation coefficient of +1.00 or -1.00 indicates a perfect linear relationship between two variables. This means that knowing the value of one variable (X) allows us to perfectly predict the value of the other variable (Y). Therefore, 100% of the variation in Y can be accounted for by knowing the value of X.

Question 7

It is important to keep in mind that correlation _______ causation.

Accepted Answer

Correlation merely shows that there is a relationship or association between two variables, but it does not provide evidence of causation. Other factors or variables may be involved, and it is important to consider alternative explanations before making causal claims based on correlation alone.

Question 8

In order to gain greater confidence that a cause-and-effect relationship exists,which of the following must be performed?

Accepted Answer

An experiment is necessary to establish cause-and-effect relationships. This involves manipulating an independent variable and measuring the effect on a dependent variable while controlling for extraneous variables.

Question 9

Glenda has determined that the correlation between the math screening test and her students' math grade is .40.What percent of the variation in math scores is accounted for by knowing the students' scores on the screening test?

Accepted Answer

The percent of variation accounted for is found by squaring the correlation coefficient. So, 0.40 squared is 0.16, which is 16%.

Question 10

A useful tool for interpreting the correlations encountered in the media and the psychological literature is to square the correlations to obtain the

Accepted Answer

Squaring the correlation coefficient yields the percent variance explained by the relationship between the two variables. This can help us better understand the strength and direction of the relationship.

Question 11

The college admissions office has determined that the correlation between IQ scores and college grade point average is .50.What percent of the variation in college grades is accounted for by knowing IQ scores?

Accepted Answer

The coefficient of determination (r^2) provides the proportion of variance in one variable (college grade point average) that can be explained by another variable (IQ score). Therefore, r^2 = .50^2 = .25, which means that knowing IQ scores accounts for 25% of the variation in college grades. Therefore, the best choice is C.

Question 12

If the correlation between the IQs of identical twins is .86,then,in any group of identical twins,what percent of the variation in the "Y" twins' IQs is accounted for by knowing the IQs of their identical siblings (the "X's")?

Accepted Answer

The correlation coefficient (r) measures the strength of the linear relationship between two variables. The coefficient of determination (r²) represents the percentage of the variation in one variable that is accounted for by the variation in the other variable. In this case, r² = 0.86² = 0.7396, which is approximately 74%. Therefore, knowing the IQs of their identical siblings can account for 74% of the variation in the Y twins' IQs.

Question 13

Regarding correlations,which of the following statements is FALSE?

Accepted Answer

Correlations do not establish causation, as there may be a third variable that is causing both of the correlated measures. While correlations can give us useful information and help us make predictions, experiments are the best way to establish causation.

Question 14

Experiments allow us to

Accepted Answer

Experiments are designed to establish causation between variables by manipulating the independent variable and observing the effects on the dependent variable. Therefore, option A is the correct choice. Option B is incorrect because nullifying a z-score does not pertain to experimentation. Option C is incorrect because demonstrating percent of variance is usually done through statistical analysis of data and does not necessarily require an experiment. Option D is partially correct as verification of extraneous variables is an important aspect of experiments, but it is not the primary purpose.

Question 15

When using correlation,we CANNOT

Accepted Answer

Correlation only shows a relationship between two variables, but it does not indicate which variable is causing the other. Therefore, we cannot conclude that a cause-and-effect relationship exists based on correlation alone.

Question 16

Regarding correlations,which of the following statements is FALSE?

Accepted Answer

It is possible for two correlated variables to have a cause-and-effect relationship. However, correlation alone cannot prove causation. A causal relationship can only be established through experimental manipulation. It is also possible for the correlation to be influenced by a third variable. Therefore, options B, C, and D are true statements regarding correlations.

Question 17

You have just read a story in the media that reports a correlation of .25 between two factors.The percent variance for this correlation would be

Accepted Answer

The percent variance explained by a correlation is found by squaring the correlation coefficient. So, 0.25 squared is 0.0625, which is 6.25 percent, approximately 6 percent.

Question 18

Regarding two variables of interest,a correlation will tell us only the degree of

Accepted Answer

A correlation tells us the strength and direction of the relationship between two variables, but it does not indicate causation or the degree of influence one variable has on the other. It also does not give information about the spread or variability between the two variables.

Question 19

When we want to generalize from the behavior of a small group to a large group,we must rely on

Accepted Answer

When we want to generalize from a small group to a large group, we must rely on inferential statistics. Descriptive statistics simply describe the data of the small group while normative statistics provide information on the ideal, optimal or standard values for a population. Random statistics is not a valid term.

Question 20

Correlations allow us to

Accepted Answer

Correlations allow us to make predictions, but they do not determine causation or demonstrate statistical significance. While correlations can be used to generalize to large samples, that is not their primary purpose.

Quiz 79: Behavioral Statistics

Which of the following would tell us the percentage of variance in one variable that can be accounted for by knowing the other variable?

Wendy has determined that the correlation between her reading screening test and her students' reading grades is .30.What percent of the variation in reading scores is accounted for by knowing the students' scores on the Screening test?

If there is a correlation of .78 between socioeconomic status and IQ score,which of the following statements is TRUE?

If the correlation between anxiety and test scores is -.85,then we can safely conclude that

If there is a .75 correlation between the hours that students devote to studying and their grades

For a correlation of +1.00 or -1.00,what percent of the variation in the Y measure is accounted for by knowing the X measure?

It is important to keep in mind that correlation _______ causation.

In order to gain greater confidence that a cause-and-effect relationship exists,which of the following must be performed?

Glenda has determined that the correlation between the math screening test and her students' math grade is .40.What percent of the variation in math scores is accounted for by knowing the students' scores on the screening test?

A useful tool for interpreting the correlations encountered in the media and the psychological literature is to square the correlations to obtain the

The college admissions office has determined that the correlation between IQ scores and college grade point average is .50.What percent of the variation in college grades is accounted for by knowing IQ scores?

If the correlation between the IQs of identical twins is .86,then,in any group of identical twins,what percent of the variation in the "Y" twins' IQs is accounted for by knowing the IQs of their identical siblings (the "X's") ?

Regarding correlations,which of the following statements is FALSE?

Experiments allow us to

When using correlation,we CANNOT

Regarding correlations,which of the following statements is FALSE?

You have just read a story in the media that reports a correlation of .25 between two factors.The percent variance for this correlation would be

Regarding two variables of interest,a correlation will tell us only the degree of

When we want to generalize from the behavior of a small group to a large group,we must rely on

Correlations allow us to