Dealing with P-Values & Correlations

Question 1

Define:

The Halo Effect.

Answer 1

When the extent to which you like a person/thing influences how positively you judge them.

(i.e. a cognitive bias leading us to transfer positive perceptions of one characteristic onto other characteristics of the same person/object).

Question 2

Define:

Covariance

Answer 2

A measure for how much the variance between two variables are related.

(i.e. how much does a difference in one variable relative to its mean simultaneously occur with differences in the other variable?)

Question 3

What kind of variables do you require for a correlation?

Answer 3

Two continuous variables.

Question 4

List:

The THREE assumptions of a Pearson’s correlation.

Answer 4

1. Independence (of measurements).
2. Normal Distribution.
3. NO extreme outliers or nonlinear patterns.

The third assumption can be checked using a scatterplot of all the data points.

Question 5

State:

Matt Hammond’s definition of a p-value.

(i.e. the definition given by the lecturer)

Answer 5

“The probability of finding the effects we found in our dataset if the null hypothesis is true”.

Question 6

List:

THREE major aspects to look for when interpretting a correlation.

Answer 6

1. Direction (+/-).
2. Magnitude.
3. Statistical Significance.

Question 7

What are some general guidelines for interpretting magnitude in a correlation?

In a Psychology context.

Answer 7

• ~.1 = weak.
• ~.3 = moderate.
• ~>.5 = strong.

However, context and theoretical influences may alter interpretations.