Chapter 11

Question 1

correlation coefficient

Answer 1

indicate the strength of association between two variables (X and Y)

Question 2

linearity

Answer 2

a straight line indicating the correlation of X and Y

Question 3

Pearson r

Answer 3

• short for Karl Pearson’s product-momentum correlation coefficient
• ranges from -1.00 to +1.00
• values of a perfect 1.00 (+/-) indicate a perfect linear relation
• • r indicates an increase in X = an increase in Y
• (-) r indicates an increase in X = a decrease in Y
• 0 indicates that neither variable can be predicted from the other

Question 4

continuous variable

Answer 4

it is possible to imagine another value falling between any two adjacent scores

Question 5

dichotomous variable

Answer 5

the variable is divided into 2 distinct or separate parts

Question 6

median split

Answer 6

creating dichotomous variables at the median point

Question 7

Phi Coefficient

Answer 7

both variables are dichotomous

Question 8

scatter plot

Answer 8

looks like a cloud of scattered dots , each dot representing the intersection at which X and Y meet

Question 9

Product -moment Correlation

Answer 9

the z-scores ( in the numerator) are distances from the mean that are multiplied by each other

Question 10

Point Bi-serial Correlation

Answer 10

• the point means that scores for one variable are points on a continuum
• biserial means that the scores for the other variable are dichotomous

Question 11

Dummy Coding

Answer 11

when numerical values such as 0 and 1 are used to indicate the two distinct parts of a dichotomous variable

Question 12

Nonlinearity

Answer 12

if the Pearson r is 0 then you are able to rule out linear correlation but not nonlinear
- can take on many different shapes such as u-shaped or wave-shaped

Question 13

Spearman rho

Answer 13

the correlation coefficient for data in the form of ranks

• typically used when when the scores to be correlated are already in ranked form