Question 1

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

Pearson correlation is typically used when the variables are both quantitative in nature and measured on a level that at least approximates interval characteristics, and when the two variables have been measured on the same individuals. Within-subjects observations are not a necessary condition for using the Pearson correlation.

Question 2

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

Smoothing techniques are used to remove noise from a scatterplot, which helps in identifying trends and patterns in the data. It does not change the regression equation or the intercept, nor does it increase the absolute value of the correlation coefficient or the probability of the r value being significant.

Question 3

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 when both variables are quantitative and on an interval or ratio level. When one variable is qualitative with three or more levels, it is not appropriate to use Pearson correlation. In such cases, other methods such as chi-square or ANOVA should be used instead.

Question 4

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...

Question 5

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 r value (-.24) indicates that as education level increases, the number of desired children decreases. Since the alpha level is set to .05 for a non-directional test, we would reject the null hypothesis if the p-value is less than or equal to .05. However, without the actual p-value, we cannot determine if the correlation is statistically significant or not. Thus, we can only conclude that a higher education level is significantly related to a smaller number of desired children.

Question 6

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 7

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

In regression analysis, the criterion variable is the outcome variable that is being predicted or explained by the predictor variable, which is the variable from which predictions are made. Therefore, option A correctly identifies the criterion variable as the variable being predicted and the predictor variable as the variable from which predictions are made.

Question 8

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 ? in the regression equation is the error score, which reflects all factors that are uncorrelated with X that influence Y. Therefore, the correct answer is E, since it reflects both options.

Question 9

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 the two variables. If r is positive, the variables have a positive correlation, meaning they increase or decrease together. If r is negative, the variables have a negative correlation, meaning as one variable increases, the other decreases. The absolute value of r indicates the strength of the relationship, where values closer to 1 indicate a stronger correlation. Therefore, examining the sign of the correlation coefficient is the best choice for determining the nature of the relationship between two correlated variables.

Question 10

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

Accepted Answer

When n is small (less than 30) and the population distribution is not normal, the sampling distribution of the correlation coefficient tends to be skewed.

Question 11

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 strength of the relationship in a correlational analysis can be calculated using the coefficient of determination (r²), which is the ratio of explained variability to total variability. Therefore, all the options (A, B, and C) are correct.

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

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 14

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. Thus, the coefficient of determination in this case is 0.62^2 = 0.3844, which is option C.

Question 15

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 for the null hypothesis that ρ = 0. Therefore, answer choice B (t-distribution) is the correct answer.

Question 16

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 standard error of estimate is calculated using the formula: SE = sqrt((1 - r^2) * (SSY / (n - 2))). Plugging in the values: SE = sqrt((1 - (-0.24)^2) * (634 / (62 - 2))) = 3.16.

Question 17

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

A bivariate normal distribution implies that the distribution of Y scores at any value of X is normal in the population, which is necessary for testing the null hypothesis that ñ = 0. The other options are not directly related to this hypothesis test.

Question 18

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

When the degrees of freedom of the Pearson correlation is 0, it means there is only one pair of scores, hence the answer is B, which corresponds to one pair.

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 best choice is D because it correctly reports the correlation coefficient and indicates that the result is significant at an alpha level of .05. The degrees of freedom are adjusted since this is a directional test, so the sample size (n) is reduced by 1 to 24. Therefore, the correct notation is r(23)= .35, p < .05.

Question 20

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...

Quiz 13: Pearson Correlation and Regression: Inferential Aspects

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

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?

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

In the regression equation of a population,the symbol ?

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

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

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

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

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 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?

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 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?

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

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

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?

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?