Correlation

Question 1

what do correlation coefficients always assume?

Answer 1

linearity and interval/ratio data

Question 2

what are scattergrams?

Answer 2

a graph where each case is plotted and each axis represents one variable

Question 3

what are the different forms relationships can take in scattergrams?

Answer 3

linear, curvilinear, independence

Question 4

what is strength of a relationship on a scattergram?

Answer 4

spread of points on a graph

Question 5

what is Pearson’s r?

Answer 5

allows us to measure direction and strength of a linear association between 2 variables

Question 6

how does Pearson’s r guess the Y value?

Answer 6

using the mean

Question 7

what does Pearson’s r assume?

Answer 7

-uses random sample
-interval/ratio level data
- normal distribution
- absence of significant outliers
- linearity

Question 8

what is the coefficient of determination?

Answer 8

a measure of explained variation; amount of variation in one variable that can be attributed to variation in the other variable

Question 9

true or false: the coefficient of determination can also be used as a measure of strength

Answer 9

true

Question 10

in a coefficient of determination, what does the remaining % represent?

Answer 10

unexplained variation; variation in Y is due to another variable that’s not X

Question 11

what is the Spearman Rho/Rank Correlation ?

Answer 11

measure of correlation used when data is ordinal (minimum level), non-linear, monotic; uses ranked values

Question 12

what is monoticity?

Answer 12

variables go up or down together

Question 13

true or false: Spearman Rho/Rank Correlation can determine causation

Answer 13

false- it can only determine correlation

Question 14

what is the halo effect?

Answer 14

assumes attractiveness means innocence`

Question 15

which researcher is well-known for studying the halo-effect?

Answer 15

Edward Thorndike