Question 1

If the researcher suspects that the strength of the relationship between two variables in the population is .15,as indexed by the correlation coefficient squared,what sample size should he use in a study involving an alpha level of .05,nondirectional test,in order to achieve a power of .99?
A)97
B)111
C)131
D)145

Accepted Answer

The answer of If the researcher suspects that the strength...

Question 2

In terms of regression,the criterion variable is ____ while the predictor variable is _____.
A)the variable being predicted;the variable from which predictions are made
B)the variable from which predictions are made;the variable being predicted
C)X;Y
D)both a and c
E)both b and c

Accepted Answer

The criterion variable is the variable being predicted (often denoted as Y), and the predictor variable is the one from which predictions are made (often denoted as X).

Question 3

If the degrees of freedom of the Pearson correlation is 0,how many pairs of scores are there?
A)0
B)1
C)2
D)cannot be determined

Accepted Answer

The degrees of freedom for the Pearson correlation coefficient is calculated as n - 2, where n is the number of pairs of scores. If the degrees of freedom is 0, then n - 2 = 0, which means n = 2. Therefore, there are 2 pairs of scores.

Question 4

A social psychologist is interested in whether education level is related the number of desired children.She obtains an r value of -.24 with 62 subjects.If the sum of squares for Y is 634,what is the estimated standard error of estimate?
A)3.16
B)3.34
C)9.96
D)11.18

Accepted Answer

The answer of A social psychologist is interested in whether...

Question 5

A psychologist believes that arousal level is related to quality of performance.He obtains measures of arousal and performance on a group of 20 people,and finds a correlation coefficient of .430.If the alpha level is .05,nondirectional test,how would this result be reported in a psychological journal?
A)r(18)= .430,p > .05
B)r(19)= .430,p > .05
C)r(20)= .430,p < .05
D)r(20)= .430,p > .05

Accepted Answer

The answer of A psychologist believes that arousal level is...

Question 6

The null hypothesis that ñ = 0 can be tested by converting the sample correlation coefficient to a statistic that has a sampling distribution that closely approximates the
A)normal distribution.
B)t distribution.
C)F distribution.
D)r distribution.

Accepted Answer

The sample correlation coefficient follows a t distribution with n-2 degrees of freedom when testing the null hypothesis that the population correlation coefficient (ñ) is equal to zero. Therefore, choice B (t distribution) is the best choice for a statistic with a sampling distribution that closely approximates the null hypothesis.

Question 7

If the researcher suspects that the strength of the relationship between two variables in the population is .40,as indexed by the correlation coefficient squared,what sample size should she use in a study involving an alpha level of .05,directional test,in order to achieve a power of .80?
A)13
B)16
C)20
D)23

Accepted Answer

The answer of If the researcher suspects that the strength...

Question 8

A social psychologist is interested in whether education level is related the number of desired children.She obtains an r value of -.24 with 62 subjects.What can we conclude from this study? Base your answer on whether the correlation is significant or not,using an alpha level of .05,nondirectional test.
A)A higher education level is significantly related to a larger number of desired children.
B)A higher education level is significantly related to a smaller number of desired children.
C)Education level is not significantly related to number of desired children.
D)Cannot be determined

Accepted Answer

The negative correlation coefficient (-.24) between education level and desired number of children indicates that as education level increases, desired number of children decreases. The p-value for this relationship would need to be less than .05 to be considered statistically significant, but this information is not given in the question. Therefore, we can only conclude that there is a significant negative relationship between education level and desired number of children based on the correlation coefficient, and the best answer choice is B.

Question 9

Which one of the following is NOT a condition under which the Pearson correlation is typically used?
A)Both variables are quantitative in nature and measured on a level that at least approximates interval characteristics.
B)The two variables have been measured on the same individuals.
C)The observations on each variable are within-subjects in nature.
D)All of these are conditions under which the Pearson correlation is typically useD.

Accepted Answer

The condition that the observations on each variable are within-subjects in nature is not typically necessary for the use of Pearson correlation. The other conditions listed (quantitative variables measured on at least an interval scale, same individuals measured on both variables) are commonly cited as requirements for using Pearson correlation.

Question 10

Based on the Applications to the Analysis of Social Problems section of Chapter 14,a smoothing technique
A)changes the slope of the regression equation to better fit the datA.
B)removes much of the noise from the scatterplot.
C)reduces the intercept of the regression line.
D)increases the absolute value of the correlation coefficient.
E)will increase the probability that the r value will be significant.

Accepted Answer

A smoothing technique is used to remove much of the noise or irregularities from a scatterplot. It is done by averaging the values of neighboring points and plotting a new line or curve that is smoother and easier to interpret. This technique does not change the slope of the regression equation, reduce the intercept, or increase the absolute value of the correlation coefficient. However, it may improve the visual representation of the relationship between variables and make it easier to identify patterns and trends.

Question 11

The nature of the relationship between two correlated variables is determined by A)calculating r². B)examining the slope of the correlation coefficient. C)examining the sign of the correlation coefficient. D)calculating Tukey's HSD.

Accepted Answer

The sign of the correlation coefficient (r) indicates the direction of the relationship between two variables. A positive r indicates a positive relationship, meaning that as one variable increases, the other variable also tends to increase. A negative r indicates a negative relationship, meaning that as one variable increases, the other variable tends to decrease. Therefore, examining the sign of the correlation coefficient is the best choice for determining the nature of the relationship between two correlated variables.

Question 12

The estimated standard error of estimate ( _XY)differs from the standard error of estimate (s_XY)in that A) _XY has N - 2 in the denominator,while s_XY has N - 1 in the denominator B) _XY has N in the denominator,while s_XY has N - 2 in the denominator C) _XY has N - 2 in the denominator,while s_XY has N in the denominator D) _XY has N - 1 in the denominator,while s_XY has N - 2 in the denominator

Accepted Answer

The answer of The estimated standard error of estimate (...

Question 13

When ñ  
0,the sampling distribution of the correlation coefficient is skewed.

Accepted Answer

The statement is true. When the sample size is less than 30 and the population distribution is not normal, the sampling distribution of the correlation coefficient tends to be skewed.

Question 14

To test the null hypothesis that ñ = 0,the scatterplot of X and Y scores should represent a bivariate normal distribution,which means that
A)the distribution of Y scores at any value of X is normal in the population
B)the distribution of Y scores is normal in the population
C)the distribution of X scores is normal in the population
D)none of these

Accepted Answer

To test the null hypothesis that ñ = 0, we need to check if there is a linear relationship between X and Y. If the scatterplot of X and Y represents a bivariate normal distribution, it means that the distribution of Y scores at any value of X is normal in the population. This is because a normal distribution is symmetric and unimodal, and if Y scores are normally distributed at any value of X, it would indicate that the relationship between X and Y is linear and that the residuals are normally distributed. Therefore, choice A is the best choice.

Question 15

The Pearson correlation cannot be used to determine the relationship between two variables when _____.
A)both variables are quantitative and on an interval level
B)both variables are measured on the same individuals and are on a ratio level
C)one variable is quantitative and the other is qualitative in nature with three or more levels
D)none of these are exceptions,it can be used in all of these cases

Accepted Answer

The Pearson correlation can only be used to determine the relationship between two quantitative variables. When one variable is qualitative in nature with three or more levels, a different type of analysis should be used, such as chi-square or ANOVA.

Question 16

In the regression equation of a population,the symbol ?
A)is the error score.
B)is the slope.
C)reflects all factors that are uncorrelated with X that influence Y.
D)both a and b
E)both a and c

Accepted Answer

The symbol "?" represents the error score in a regression equation, which reflects all factors that are uncorrelated with X that influence Y. Therefore, both options E (both a and c) are correct. Option A (is the error score) is only partially correct since it does not account for the fact that the error score represents all uncorrelated factors that influence Y. Option B (is the slope) is incorrect.

Question 17

The strength of the relationship in a correlational analysis can be calculated with A)a ratio of explained variability to total variability. B)r² C)the coefficient of determination D)both a and b E)all of these

Accepted Answer

The answer of The strength of the relationship in a...

Question 18

A researcher was interested in whether testosterone was related to aggression.Testing 18 male subjects,he found a correlation coefficient of .62.What is the coefficient of determination?
A).15
B).38
C).3844
D).62

Accepted Answer

The coefficient of determination is the square of the correlation coefficient, so (0.62)^2 = 0.3844. Therefore, the answer is C.

Question 19

A researcher believes that an extroverted personality is positively related to self-esteem.She obtains measures of both variables for 25 people,and calculates a correlation coefficient of .35.If the alpha level is .05,directional test,how would this result be reported in a psychological journal?
A)r(25)= .35,p < .05
B)r(24)= .35,p < .05
C)r(23)= .35,p > .05
D)r(23)= .35,p < .05

Accepted Answer

The correct choice is D because the researcher is using a directional test (they predict a positive correlation) and the p-value (probability value) is less than .05, which means there is a statistically significant positive correlation between extroverted personality and self-esteem among the 25 participants. The degrees of freedom are calculated as (25-2) = 23, so the correlation coefficient is reported as r(23) = .35. Therefore, the correct way to report this result in a psychological journal would be: "A significant positive correlation was found between extroverted personality and self-esteem among 25 participants (r(23) = .35, p < .05, one-tailed)."

Question 20

A researcher was interested in whether testosterone was related to aggression.Testing 18 male subjects,he found a correlation coefficient of .62.If the standard deviation estimate for Y was 13.2,what is the estimated standard error of estimate?
A)2.94
B)5.17
C)8.63
D)10.68

Accepted Answer

The answer of A researcher was interested in whether testosterone...

Quiz 14: Pearson Correlation and Regression: Inferential Aspects

If the researcher suspects that the strength of the relationship between two variables in the population is .15,as indexed by the correlation coefficient squared,what sample size should he use in a study involving an alpha level of .05,nondirectional test,in order to achieve a power of .99?

In terms of regression,the criterion variable is while the predictor variable is _.

If the degrees of freedom of the Pearson correlation is 0,how many pairs of scores are there?

A social psychologist is interested in whether education level is related the number of desired children.She obtains an r value of -.24 with 62 subjects.If the sum of squares for Y is 634,what is the estimated standard error of estimate?

The null hypothesis that ñ = 0 can be tested by converting the sample correlation coefficient to a statistic that has a sampling distribution that closely approximates the

If the researcher suspects that the strength of the relationship between two variables in the population is .40,as indexed by the correlation coefficient squared,what sample size should she use in a study involving an alpha level of .05,directional test,in order to achieve a power of .80?

Which one of the following is NOT a condition under which the Pearson correlation is typically used?

Based on the Applications to the Analysis of Social Problems section of Chapter 14,a smoothing technique

The nature of the relationship between two correlated variables is determined by

The estimated standard error of estimate ( _XY) differs from the standard error of estimate (s_XY) in that

When ñ 0,the sampling distribution of the correlation coefficient is skewed.

To test the null hypothesis that ñ = 0,the scatterplot of X and Y scores should represent a bivariate normal distribution,which means that

The Pearson correlation cannot be used to determine the relationship between two variables when _____.

In the regression equation of a population,the symbol ?

The strength of the relationship in a correlational analysis can be calculated with

A researcher was interested in whether testosterone was related to aggression.Testing 18 male subjects,he found a correlation coefficient of .62.What is the coefficient of determination?

A researcher believes that an extroverted personality is positively related to self-esteem.She obtains measures of both variables for 25 people,and calculates a correlation coefficient of .35.If the alpha level is .05,directional test,how would this result be reported in a psychological journal?

A researcher was interested in whether testosterone was related to aggression.Testing 18 male subjects,he found a correlation coefficient of .62.If the standard deviation estimate for Y was 13.2,what is the estimated standard error of estimate?