Research Methods: Chapters 8

Question 1

Explain the Directionality and the Third-Variable Problems.

Answer 1

Directionality Problem - When we don’t know which variable came first.
Third-Variable Problem - When there could be an alternate explanation for the association between the two variables.

Question 2

What is the Pearson Product-Moment Correlation Coefficient (r)?

Answer 2

• A number that tells us how strong the relationship is between two variables.
• Ranges from -1.0-+1.0
  r = Σ(Zx)(Zy)/N-1

Question 3

What is the Probability Estimate (p)?

Answer 3

• The probability that the sample’s association came from a population in which the association is zero.
• The probability of making a Type 1 Error
• p or sig(significance)
  -The probability of being wrong is 0.05 or below
  
  • Either significant or not (nonsignificant), not in between.

Question 4

What is Effect Size? What does it mean to have a larger (or stronger) effect size?

Answer 4

Effect Size - Describes the strength between two or more variables.
x < .10 = weak
.10< x > .50 = moderate
x > .50 = string
Having a larger effect size allows for more accurate predictions and is usually more important

Question 5

What does a Statistically Significant and Nonsignificant Result Mean?

Answer 5

If the probability (p) associated with the result is very small (0.05 / 5% or less), we know that the result is very unlikely to have come from a zero-association population.
If the probability (p) associated with the result is higher than 0.05 / 5%, we know that the result is not unlikely to have come from a zero-association population.

Question 6

What is Restriction of Range?

Answer 6

When there is not a full range of scores on one of the variables in the association, the correlation appears smaller than it really is.

Question 7

Explain Spurious Association.

Answer 7

A relationship in which two or more variables are associated but not causally related, due to either coincidence or a third variable.

Question 8

What is a Moderator?

Answer 8

When the relationship between two variables changes depending on the level of another variable, that other variable is called a moderator.

Question 9

What is a Bivariate Correlation?

Answer 9

An association that involves exactly two variables.