QM thangs

Question 1

Correlation coefficient

Answer 1

can be positive or negative, range from -1 to 1. 0 indicates no association between the two variables. Small effect: .10 .50

Question 2

R-squared

Answer 2

the percentage of variance shared by the two variables

Question 3

null for correlation

Answer 3

the correlation is zero

Question 4

Spearman correlation coefficient

Answer 4

used when the data is ordinal (ranked) and one-directional but not linear

Question 5

Regression model equation

Answer 5

Y (outcome variable) = a (intercept) + b(slope) X (predictor variable)+ (error)

Question 6

Error in the equation is assumed to be

Answer 6

• Independent
• Normally distributed
• Homoscedastic

Question 7

F test (ANOVA)

Answer 7

Whether the variance explained is significantly different from zero
- if the f test is not signifiant, the regression is worthless. the predictor does not explain the outcome variable at all.