Deck 13: Correlation: Understanding Covariation

Question 1

13-12 If values of one variable in a scatterplot increase while the values of the other decrease, then the relationship is described as.

A)direct
B)indirect
C)positive
D)negative

Answer 1

D

Question 2

13-14 The Pearson correlation coefficient is used.

A)to quantify the relationship between two variables in a bivariate distribution
B)to quantify the relationship between two variables in a one-variable distribution
C)when pairs of scores achieve ordinal measurement
D)to test a null hypothesis about the means in a bivariate distribution

Answer 2

A

Question 3

13-20 The CPXY is given by.

Answer 3

C

Question 4

13-11 Relationships between two variables that can be described by a straight line are called relationships.

A)direct
B)normal
C)correlational
D)linear

Question 5

If two variables covary, then.

A)a change in one variable is not accompanied by a consistent change in the other variable
B)as one variable increases, the other must decrease
C)a change in one variable is accompanied by a consistent change in the other variable
D)the two variables have the same mean

Question 6

13-15 The Pearson correlation coefficient is symbolized as.

A)R
B)r
C)P
D)PC

Question 7

A plot or graph of the relationship between two variables is known as a.

A)scatterplot
B)histogram
C)bimodal distribution
D)correlational plot

Question 8

13-10 A linear relationship between two variables can be described by a.

A)right angle
B)straight line
C)mean and standard deviation
D)curved line

Question 9

When two scores are obtained from each participant, a distribution is obtained.

A)normal
B)one variable
C)bivariate
D)straight line

Question 10

If two variables are related so that increasing values of one variable are associated with increasing values of the other, then there is a (or ) relationship between the variables.

A)positive; direct
B)positive; inverse
C)negative; direct
D)negative; inverse

Question 11

If two variables are related so that as values of one variable increase the values of the other also increase, then the relationship is said to be.

A)positive
B)negative
C)inverse
D)indirect

Question 12

A scatterplot is a graph of a distribution.

A)one variable
B)normal
C)bimodal
D)bivariate

Question 13

13-16 The Pearson correlation coefficient is used.

A)to quantify the relationship between two variables in a one-variable distribution
B)to determine the amount of variability in a set of scores
C)when pairs of scores achieve either interval or ratio measurement
D)to test a null hypothesis about the means in a bivariate distribution

Question 14

13-19 The cross products of X and Y are symbolized by.

A)CPXY
B)Cross XY
C)XProd
D)XPXY

Question 15

The direction and degree of the relationship of two variables are assessed with.

A)a between-subjects design
B)correlational research
C)the analysis of variance
D)the tind test

Question 16

A representation of a relationship between two variables in graphic form is a distribution.

A)one variable
B)bivariate
C)bimodal
D)normal

Question 17

13-18 When calculating the Pearson correlation coefficient, is called the of X and Y.

A)sum of squares
B)cross products
C)standard deviation
D)correlation

Question 18

A correlational study is designed to.

A)determine the relationship between an independent variable and a dependent variable
B)describe the degree of central tendency for a variable
C)find the extent to which two variables are related
D)manipulate an independent variable

Question 19

13-13 If two variables are related so that increasing values of one variable are associated with decreasing values of the other, then there is a (or ) relationship between the variables.

A)positive; direct
B)positive; inverse
C)negative; inverse
D)negative; direct

Question 20

13-17 The numerator of the Pearson r is the.

A)product of the sums of squares for the X and Y values
B)square root of the sum of squares for X plus the sum of squares for Y
C)sum of the cross products of X and Y divided by N
D)cross products of X and Y

Question 21

13-30 If you calculated robs = +1.57, then.

A)the two variables are more than perfectly positively related
B)the two variables are strongly, but not perfectly, positively related
C)the two variables are not at all related
D)you would know you had made a mistake in calculation

Question 22

13-33 When robs equals zero, the scatterplot of X and Y will most closely resemble a(n).

A)straight line
B)narrow ellipse
C)circle
D)oval

Question 23

13-42 How will r be affected by decreasing the range of values of variable X?

A)The value of r will increase.
B)The value of r will decrease.
C)The value of r will either increase or decrease depending on the value of the cross products.
D)The value of r will be unaffected.

Question 24

13-36 Which correlation coefficient represents the weakest association between the X and Y variables?

A)r = +.20
B)r = +.60
C)r = -.50
D)r = -.90

Question 25

13-41 A study has found a negative correlation between a person's income and his or her blood pressure. This study indicates that.

A)income and blood pressure are not related
B)higher income is associated with higher blood pressure
C)as income increases, blood pressure tends to increase also
D)higher income is associated with lower blood pressure

Question 26

13-35 The scatterplot depicting a relationship between two variables for which r = -.90 would be a.

A)narrow ellipse
B)circle
C)wide oval
D)straight line

Question 27

13-22 If the X and Y scores of a bivariate distribution are not related, then the CPXY on these scores should be.

A)equal to either +1.00 or -1.00
B)a large positive value
C)a large negative value
D)equal to about zero

Question 28

13-37 A Pearson r should be calculated only when the relationship between two variables can be assumed to be.

A)independent
B)linear
C)positive
D)negative

Question 29

13-39 Researchers have found a negative correlation between the number of hours a high school student works and high school achievement. Given this knowledge, you would expect that.

A)more hours worked per week are associated with greater high school achievement
B)more hours worked per week are associated with lower high school achievement
C)there is no relation between number of hours worked per week and high school achievement
D)if you knew the number of hours worked per week it would not help you predict the student's high school achievement

Question 30

13-40 Crime rates usually are positively related to population density. Thus you expect that.

A)high population density areas would have low crime rates
B)higher population density is associated with lower crime rates
C)higher population density is associated with higher crime rates
D)population density and crime rate are not related

Question 31

13-26 The value of r may lie within an interval of values ranging from.

A)-1.00 to +1.00
B)0.00 to +10.00
C)-10.00 to 0.00
D)0.00 to -1.00

Question 32

13-31 Which of the following values of robs allows perfect prediction of the Y score from knowledge of the X score?

A)zero
B)+1.00
C)+.50 d +2.00

Question 33

13-25 The direction of a linear relationship between two variables is given by of r.

A)the numerical value
B)the plus or minus sign
C)both the sign and numerical value
D)the numerical value of the denominator

Question 34

13-29 If two variables are completely unrelated, robs.

A)equals zero
B)equals either +1.00 or -1.00
C)is a large value but not +1.00 or -1.00
D)is greater than 1.00

Question 35

13-21 The denominator of the Pearson r is.

Question 36

13-38 A psychologist has found a correlation of +.54 between measures of need for achievement and college grade point average. Given this knowledge, you would expect that.

A)higher need for achievement scores are associated with higher college grade point averages
B)higher need for achievement scores are associated with lower college grade point averages
C)there is no relationship between need for achievement and college grade point average
D)if you knew a student's need for achievement score, you could predict the student's grade point average perfectly

Question 37

13-28 A perfect linear relationship of variables X and Y would result in a value of robs equal to .

A)zero
B)a large value but not +1.00 or -1.00
C)a small value but not zero
D)either +1.00 or -1.00

Question 38

13-34 The pattern of scores in a scatterplot that indicates no relationship between two variables is.

A)oval
B)circular
C)elliptical
D)linear

Question 39

13-24 The sign of r indicates the of the relationship between two variables.

A)strength
B)direction
C)magnitude
D)degree

Question 40

13-27 The range of values that r can assume is.

A)0.00 to +10.00
B)0.00 to -10.00
C)-1.00 to +1.00
D)none of the above

Question 41

13-57 In a test to determine if r is statistically significant, H0 is.

A)r = 0
B)r = 1
C)ρ ≠ 0
D)ρ = 0

Question 42

13-48 The extent to which two variables share common variance is estimated by.

Question 43

13-51 If robs = +.40, then percent of the variance in the scores of one variable is associated with variation in the other variable.

A)40
B)60
C)16
D)8

Question 44

13-61 If robs does not fall into a rejection region, then the decision is to H0 and H1.

A)accept; reject
B)reject; accept
C)fail to reject; not accept
D)reject; not accept

Question 45

13-43 If the scores of either the X or Y variable are restricted in value, then we expect

A)a larger value of r than if the scores were not restricted in value
B)r to equal either +1.00 or -1.00
C)a smaller value of r than if the scores were not restricted in value
D)it will have no effect on r

Question 46

13-60 If robs falls into a rejection region, then the decision is to H0 and H1.

A)accept; reject
B)reject; accept
C)fail to reject; not accept
D)reject; not accept

Question 47

13-53 If variables X and Y are correlated, then which of the following is a possibility?

A)X causes Y.
B)Y causes X.
C)X and Y may be caused by a third variable, Z.
D)All the above are possibilities.

Question 48

13-56 The population correlation coefficient is represented by the symbol.

A)α
B)β
C)μ
D)ρ

Question 49

13-58 In a test to determine if r is statistically significant, H1 is.

A)r = 0
B)r = 1
C)ρ ≠ 0
D)ρ = 0

Question 50

13-50 If robs = -.60, then percent of the variance in the scores of one variable is associated with variation in the other variable.

A)60
B)36
C)40
D)64

Question 51

13-49 The value of is a measure of the.

A)extent to which two variables share a common variance
B)precision with which one variable predicts the value of the other
C)degree of linear association between two variables
D)degree of nonlinear association between two variables

Question 52

13-59 In a test to determine if r is statistically significant, the df for robs are equal to.

A)Npairs - 2
B)Npairs
C)Npairs - 1
D)Npairs + 2

Question 53

13-44 If the range of one or both variables is restricted, then the value of r for these variables most likely will.

A)not change
B)become either +1.00 or -1.00
C)increase
D)decrease

Question 54

13-62 You obtained robs = +.39 when correlating the number of hours per week spent studying by a student and his or her grade point average. In order to find if this correlation coefficient is statistically significant, you need to know the.

A)means for both variables
B)standard deviation for both variables
C)number of pairs of scores on which robs was based
D)CPXY for this correlation

Question 55

13-64 An assumption of the statistical test for the significance of r is that.

A)the variances of X and Y are equal
B)the means of the X and Y populations are equal
C)the X and Y scores are statistically independent
D)both the X and Y scores are normally distributed in the population sampled

Question 56

13-63 An assumption of the statistical test for the significance of r is that the.

A)variances of X and Y are equal
B)means of the X and Y populations are equal
C)X and Y scores form a bivariate normal distribution
D)X and Y scores are statistically independent

Question 57

13-47 The proportion of variance in one variable that is associated with variance in the other variable is given by.

Question 58

13-54 If variables X and Y are correlated, then which of the following is not a possibility?

A)X causes Y.
B)X and Y are independent of each other..
C)Y causes X.
D)X and Y may be caused by a third variable, Z.

Question 59

13-52 If the coefficient of determination equals .49, then r equals.

Question 60

13-55 The symbol ρ represents the.

A)population correlation coefficient
B)sample correlation coefficient
C)magnitude of the strength of association
D)coefficient of determination

Question 61

13-75 If the results of a study using the Spearman correlation coefficient were reported as rS(17) = +.63, p < .05, then you would know that H0 was and was.

A)ρS = 1; rejected
B)ρS = 1; not rejected
C)ρS = 0; rejected
D)ρS = 0; not rejected

Question 62

13-67 If the results of a correlational study were reported as r(42) = +.26, p > .05, then you would know that H0 was and was.

A)ρ = 1; rejected
B)ρ = 1; not rejected
C)ρ = 0; rejected
D)ρ = 0; not rejected

Question 63

13-80 If the results of a study using the Spearman correlation coefficient were reported as rS(16) = -.34, p > .05, then you would know that subjects participated in the study.

A)12
B)16
C)14
D)18

Question 64

13-76 If the results of a study using the Spearman correlation coefficient were reported as rS(23) = -.32, p > .05, then you would know that H0 was and was.

A)ρS = 1; rejected
B)ρS = 1; not rejected
C)ρS = 0; rejected
D)ρS = 0; not rejected

Question 65

13-74 In testing the statistical significance of rS, the critical value is based upon.

A)Npairs
B)Npairs - 1
C)Npairs - 2
D)the total number of scores minus one

Question 66

13-79 If the results of a study using the Spearman correlation coefficient were reported as rS(29) = -.24, p > .05, then which of the following statements is true?

A)H1 was accepted.
B)The value of Npairs was 29.
C)The X and Y variables are significantly negatively related.
D)All the above.

Question 67

13-68 If the results of a correlational study were reported as r(48) = -.47, p < .05, then which of the following statements is true?

A)robs is statistically significant at the .05 level.
B)H0 was ρ = + or - .47.
C)rcrit = + or - .47.
D)H1 was ρ = 0.

Question 68

13-77 If the results of a study using the Spearman correlation coefficient were reported as rS(28) = -.44, p < .05, then which of the following statements is true?

A)H0 was ρS = + or - .44.
B)The X and Y variable are significantly negatively related.
C)rS crit = + or - .44.
D)H1 was ρS = 0.

Question 69

13-69 If the results of a correlational study were reported as r(14) = +.23, p > .05, then which of the following statements is true?

A)H0 was ρ = 0.
B)H0 was not rejected.
C)robs was +.23.
D)All the above.

Question 70

13-72 The Spearman r describes the relationship between pairs of scores that represent measurement.

A)ratio
B)interval
C)ordinal
D)nominal

Question 71

13-65 If the results of a correlational study were reported as r(12) = -.32, p > .05, then you would know that subjects participated in the study.

A)10
B)14
C)13
D)12

Question 72

13-70 If the results of a correlational study were reported as r(26) = -.53, p < .05, then which of the following statements is true?

A)H1 was accepted.
B)The value of Npairs was 28.
C)The X and Y variables are significantly negatively related.
D)All the above.

Question 73

13-66 If the results of a correlational study were reported as r(20) = +.57, p < .05, then you would know that H0 was and was.

A)ρ = 1; rejected
B)ρ = 1; not rejected
C)ρ = 0; rejected
D)ρ = 0; not rejected

Question 74

13-78 If the results of a study using the Spearman correlation coefficient were reported as rS(18) = +.57, p < .05, then which of the following statements is true?

A)H0 was ρS = 0.
B)H0 was rejected.
C)rS obs was +.57.
D)All the above.

Question 75

13-73 The Spearman correlation coefficient is symbolized by.

A)RS
B)rS
C)Spear r
D)RSpearman

Question 76

13-71 The Spearman correlation coefficient is used for data.

A)categorized
B)ranked
C)continuous
D)discrete