Regression/Scatter graphs

Question 1

Models coefficient of determination found how?

Answer 1

R2

Question 2

Positive linear graphs represented how?

Answer 2

if one variables increase, so does the other one (x increases so does y)

Question 3

Negative linear graphs represented how?

Answer 3

if one variable increases, the other decreases (x decreases but y increases)

Question 4

Non linear graphs are?

Answer 4

curved, not in a straight line

Question 5

Pearsons strength of correlation measures what?

Answer 5

how much 2 variables change together; measure of association between them

Question 6

Pearson strength of correlation values?

Answer 6

1. Perfect positive correlation
   0.7 - 0.9. Strong
   0.6 - 0.4. Moderate
   0.3 - 0.1. Weak
   0 Zero
   -1 perfect negative correlation

Question 7

Regression analysis formula

Answer 7

y = a+bx

Question 8

P values of coefficient give what?

Answer 8

p values in a regression model give the probability that the coefficient in question are close to zero

Question 9

If p value lower than 5%?

Answer 9

the coefficient is statistically significant

Question 10

Coefficient of determination, close to 1 shows?

Answer 10

represents a good fit and represents the total variation of the dependent variable that is explained by the regression line

Question 11

R2 Percentage values and meanings?

Answer 11

under 60% not useful
over 60% useful
above 80% ideal

Question 12

Assessing the model of case study… what to look for?

Answer 12

Is independent variable suitable?
 correlation coefficient (r) = ?
 strong association
 p-value = ?
 statistically significant at less than 1%
 Is the coefficient of determination (R2) close to 1?
 Model probably adequate for forecasting!

Question 13

If p value higher than 5%?

Answer 13

the coefficient is statistically insignificant