Deck 11: Correlating Variables

Question 1

The correlation coefficient computed between two dichotomous variables is the

A) Spearman rho.
B) phi coefficient.
C) point-biserial correlation.
D) Spearman-Brown coefficient.

Answer 1

B

Question 2

The product-moment (Pearson r) correlation coefficient is used to measure the __________ relationship between two variables.

A) causal
B) positive
C) directional
D) linear

Answer 2

D

Question 3

Steve wants to examine the linear relation between the number of times a commercial appears on television and the dollar sales of the advertised product. Which of the following correlation coefficients should Steve calculate?

A) product-moment correlation coefficient
B) Spearman rho
C) point-biserial correlation
D) phi coefficient

Answer 3

A

Question 4

In a recent study, Mary found a correlation coefficient of .83 between the two variables, foot size and score on the math final. She concludes that these two variables have a strong ________ correlation.

A) negative
B) positive
C) binary
D) continuous

Question 5

What is another term for dichotomous?

A) binary
B) correlation
C) Spearman rho
D) continuous

Question 6

Another name for the product-moment correlation is the

A) Spearman rho.
B) point-biserial correlation.
C) phi coefficient.
D) Pearson r.

Question 7

Tom wants to determine whether spending more time studying will improve his overall class percentage grade. Statistically speaking, Tom wants to know if there is a __________ between studying and class performance.

A) positive correlation
B) negative correlation
C) zero correlation
D) nonlinear correlation

Question 8

Charles finds that the correlation coefficients between his predictor variable and three different outcome variables are +.23, +.45, and -.53. Which correlation coefficient indicates the strongest linear relation that Charles found between his predictor and outcome variables?

A) +.23
B) +.45
C) -.53
D) not enough information is provided

Question 9

If one wanted to assess the magnitude of the relationship between a continuous variable and a dichotomous variable, one would calculate a

A) point-biserial correlation.
B) Spearman rho.
C) phi coefficient.
D) Spearman-Brown coefficient.

Question 10

Cameron wishes to correlate college football team rankings at the end of this year's football season with the rankings from the previous year. Which correlation coefficient should Cameron use?

A) Spearman rho
B) phi coefficient
C) point-biserial correlation
D) any of the above

Question 11

Donna is calculating the correlation coefficient between two continuous variables. Which correlation coefficient should Donna use?

A) Product-moment correlation coefficient
B) Spearman rho
C) point-biserial correlation
D) phi coefficient

Question 12

Amala wants to observe the relation between where her teammates placed in one cross-country meet and where they placed in the next cross-country meet against the same opponents. Which correlation coefficient should Amala use to examine this relation?

A) phi coefficient
B) point-biserial correlation
C) product-moment correlation coefficient
D) Spearman rho

Question 13

The correlation computed on two data sets that are in the form of ranks is usually called the

A) point-biserial correlation.
B) phi coefficient.
C) Spearman rho.
D) product-moment correlation.

Question 14

A graph that can be used to visualize the correlation coefficient is the

A) line graph.
B) bar graph.
C) stem-and-leaf chart.
D) scatter plot.

Question 15

Brian is interested in whether there is a relationship between one's gender and the length of time spent talking on the phone. Which correlation coefficient should Brian use?

A) phi coefficient
B) point-biserial correlation
C) Spearman rho
D) Spearman-Brown coefficient

Question 16

Dummy coding is often used to quantify __________ data.

A) incomplete
B) continuous
C) sample
D) dichotomous

Question 17

The __________ of the correlation coefficient indicates the direction of the relationship; the __________ indicates the strength of the relationship.

A) value; sign
B) linearity; magnitude
C) sign; value
D) magnitude; linearity

Question 18

With __________ variables, one can imagine that there can always be another value between two adjacent scores. On the other hand, __________ variables have their values divided into two mutually exclusive categories.

A) random; dichotomous
B) continuous; dichotomous
C) dichotomous; continuous
D) continuous; random

Question 19

In a scatter diagram, the more tightly clustered the data points are around a straight line, the __________ the correlation coefficient is between the two variables.

A) lower
B) higher
C) closer to zero
D) weaker

Question 20

A __________ correlation coefficient means that decreases in X are associated with decreases in Y; a __________ correlation coefficient means that decreases in X are associated with increases in Y.

A) positive; negative
B) zero; negative
C) negative; positive
D) positive; zero

Question 21

Why is the Pearson r also referred to as the product-moment correlation coefficient?

Question 22

What does it mean to say that two variables are linearly related? How can this relationship be measured?

Question 23

What is dummy coding? Why is it sometimes used to compute a correlation coefficient?

Question 24

What is the difference between a positive, a negative, and a zero correlation?

Question 25

Terri is intrigued about a possible relation between whether one is left-handed or right-handed and one's gender. Which correlation coefficient should Terri calculate to examine this possible relation?

A) phi coefficient
B) point-biserial correlation
C) Spearman rho
D) product-moment correlation coefficient

Question 26

What are the four types of correlation coefficients discussed in the text? When is it appropriate to use each one?

Question 27

A 2 × 2 table of counts can be useful when computing which correlation coefficient?

A) Spearman rho
B) point-biserial
C) phi coefficient
D) Spearman-Brown coefficient