Chapter 8 Correlation

Question 1

Strength Magnitude

Answer 1

A characteristic of a correlation with a focus on how strongly 2 variables are related.

Question 2

Causation

Answer 2

The concept that variations in one variable CAUSES variation in another variable

Question 3

Correlation Coefficient

Answer 3

A statistic that reveals the strength and direction of the relationship b/w 2 variables

Question 4

Coefficient of Determination

Answer 4

A stat found by squaring the Pearson Correlation Coefficient that reveals the % of variance explained in each of the 2 correlated variables by the other variable

Question 5

Shared Variance

Answer 5

The concept of 2 variables overlapping such that some of the variance in each variable is shared. The stronger the correlation b/w the 2 variables the greater the amt. of shared variance b/w them.

Question 6

Scattergram / Scatterplot

Answer 6

A graphical depiction of each member of a distribution score on 2 variables simultaneously

Question 7

Positive Correlation

Answer 7

A characteristic of a correlation when the scores on the 2 correlated variables move in the same direction, on average.
As the scores of one variable rise, scores on the other variable rise and vice versa.

Question 8

Perfect Positive Correlation

Answer 8

A correlation coefficient of r = +1.0 occurs when increases in scores of a given size on one of the variables in a correlation are associated with increased scores of a related size on a second variable in the correlation.

(e.g. for each 1 - unit increased in the score on a variable X there is a corresponding 2 - unit increase in the scores on variable Y)

Question 9

Perfect Negative Correlation

Answer 9

A correlation Coefficient of r = - 1.0 occurs when the increasing scores of a given size on one of the variables in a correlation are associated with decreasing scores of related size on a second variable in the correlation.

(i.e. for each 1 - unit increase in the score on variable X there is a corresponding 2 - unit DECREASE in scores on Y variable.

Question 10

Pearson Product - Moment Correlation Coefficient

Answer 10

A statistic indicating the strength and direction of the relation b/w 2 continuous variables.

Question 11

Negative Correlation

Answer 11

A descriptive feature of a correlation indicating that as scores on one of the correlated variables increase scores on the other variable decrease and vice versa

Question 12

Dichotomous Variable

Answer 12

A categorical, or nominal variable with 2 categories.

Question 13

Direction

Answer 13

A characteristic of a correlation that describes whether 2 variables are positively or negatively related to each other.

Question 14

Explained Variance

Answer 14

The % of variance in one variable that we can account for, or understand, by knowing that value of the 2 variables in the correlation.

Question 15

Cross Products

Answer 15

The product of multiplying each individual scores on 2 variables

Question 16

Curvilinear

Answer 16

A relationship b/w 2 variables that is positive at some values but negative at other values.

Question 17

Covariance

Answer 17

The average of the cross products of a distribution.

Question 18

Truncated Range

Answer 18

When the response of a variable are clustered near the top or bottom of the possible range of scores, thereby limiting the range of scores and possibly limiting the strength of the correlation.

Question 19

Z Score

Answer 19

Standard Score

Question 20

r

Answer 20

The Sample Pearson Correlation Coefficient

Question 21

p

Answer 21

Rho, the population correlation coefficient

Question 22

Sr

Answer 22

The standard error of the correlation coefficient

Question 23

r2

Answer 23

The Coefficient of Determination

Question 24

Degrees of Freedom (df)

Answer 24

Min. amt of data needed to calculate a statistic. More practically, it is the number(s), used to approximate the number of observations in the data set for the purpose of determining statistical significance.