Correlation Exam 2

Question 1

Pearson correlation coefficient

Answer 1

Measure of the linear relationship between two continuous variables

Question 2

Pearson correlation coefficient possible values

Answer 2

• 0 < r < 1
• 0 > r > -1
• r = 0

Question 3

Pearson correlation coefficient: 0 < r < 1

Answer 3

indicates a positive correlation (as one variable increases, the second variable also increases)

Question 4

Pearson correlation coefficient: 0 > r > -1

Answer 4

indicates a negative correlation (as one variable increases, the second variable decreases)

Question 5

Pearson correlation coefficient: r = 0

Answer 5

indicates no linear relationship

Question 6

When using a Pearson correlation coefficient, does the measurements need to be on the same scale?

Answer 6

no

Question 7

Spearman rank correlatioan

Answer 7

• AKA Spearman Rho Coefficient

- Continuous data can be transformed into ranks, then used to calculate Spearman r(s)

Question 8

Spearman rank correlatioan possible values

Answer 8

-1 and +1

Question 9

Phi Coefficient

Answer 9

• Estimates the extent of the relationship between two binary variables

Question 10

Phi Coefficient possible values

Answer 10

• -1 to +1

* The closer the value is to 1, the stronger the relationship

Question 11

Kappa Coefficient

Answer 11

• AKA Cohen’s Kappa
• Used to examine inter-rater agreements
• The greater the number, the more agreement there is

Question 12

Kappa Coefficient possible values

Answer 12

0 to 1

Question 13

Kappa Coefficient: 0

Answer 13

no more agreement between two raters as can be expected on the basis of chance

Question 14

Kappa Coefficient: 1

Answer 14

perfect agreement (all observations on the diagonal)

Question 15

If you have nominal data, which one would you use?

Answer 15

• Phi coefficient (Φ)

- Kappa coefficient (Κ)

Question 16

If you have ordinal data, which one would you use?

Answer 16

Spearman rho [r(s)], continuous data that are not normally distributed

Question 17

If you have interval data, which one would you use?

Answer 17

Pearson (r)

Question 18

If you have ratio data, which one would you use?

Answer 18

Pearson (r)

Question 19

What kind of data do you use with the Phi coefficient (Φ)?

Answer 19

nominal

Question 20

What kind of data do you use with the Kappa coefficient (Κ)?

Answer 20

nominal

Question 21

What kind of data do you use with the Spearman rho [r(s)]?

Answer 21

ordinal

Question 22

What kind of data do you use with the Pearson (r)?

Answer 22

• interval

- ratio

Question 23

What is the null hypothesis for the Pearson (r)?

Answer 23

H0: ρ = 0

Question 24

Kappa Coefficient interpretation

Answer 24

• Lower than 0.4 = poor agreement
• 0.4 to 0.75 = fair to good agreement
• Higher than 0.75 = excellent agreement