Lecture #8 (Correlation)

Question 1

What are we arguing in correlation?

Answer 1

We are arguing that there is a trend between two variables (Shoe size and height)

Question 2

How do we measure correlation?

Answer 2

Between -1 and +1 where the closer to 1 you get, the stronger the correlation

Question 3

What is Pearson’s R used for?

Answer 3

Pearson’s R is used for measuring the variability between two datasets

Question 4

What is the formula for Pearson’s R?

Answer 4

r = (Σ(xᵢ - x̅)(yᵢ - ȳ)) / √(Σ(xᵢ - x̅)² Σ(yᵢ - ȳ)²)

Question 5

What are some assumptions we have while using Pearson’s r?

Answer 5

Data is normally distributed and is ratio data

Question 6

In Pearson’s r, is the data independent from eachother?

Answer 6

Yes

Question 7

What do we use Spearman’s Rank Correlation Coefficient for?

Answer 7

For ordinal and interval data, uses rank instead of values

Question 8

What is Kendall’s Tau Rank Correlation Coefficient rτ?

Answer 8

Like Spearman’s but has zero assumptions about data distribution

Question 9

Does Kendalls’s looks at conformity (concordance) and disagreement (discordance) in the rankings?

Answer 9

Yes

Question 10

What is the Phi Correlation Coefficient (rф)?

Answer 10

This measures the degree of association between data that has been categorized into binary data

Question 11

What is Phi close to?

Answer 11

Chi Squared