Research Methods

Question 1

What are the 3 categories of quantitative psychological research?

Answer 1

Difference
Association
Prediction

Question 2

What do we mean when we test for difference?

Answer 2

Is one group of people different to another in some aspect?

Question 3

What do we mean when we test for association?

Answer 3

Is one construct related to another?

Question 4

What do we mean when we test for a prediction?

Answer 4

Does one construct influence another?

Question 5

What is a typical score?

Answer 5

A score that is within 2 std devs from the mean

Question 6

What is an extreme score?

Answer 6

A score that is outside 2 std devs from the mean

Question 7

What is a distribution of sample means?

Answer 7

All the sample means from all the samples of a certain size that could possibly be taken from a population?

Question 8

What are the two things that the central limit theorem tells us about the distribution of sample means?

Answer 8

The mean of the distribution of the sample is the same as the population mean.

The distribution of sample means will have a normal shape for sample sizes 30+

Question 9

What is the standard error?

Answer 9

The std dev of the distribution of sample means

Question 10

What happens to the std dev as the sample size increases?

Answer 10

The std dev decreases.

Question 11

How can you describe the null hypothesis?

Answer 11

The hypothesis of no effect.

Question 12

How do we do null hypothesis significance testing?

Answer 12

Proceed assuming that the null hypothesis is true.
If the probability of the sample mean occuring is small (generally <0.05/ aka an extreme score), REJECT the null hypothesis. If the probability is large, DO NOT REJECT the null hypothesis.

Question 13

What is the alpha level?

Answer 13

The level of significance, which is 5%/ 0.05.

Question 14

How many std errors away are the alpha levels from the distribution mean?

Answer 14

1.96 std errors.

Question 15

What does a z-score express?

Answer 15

The amount of std errors a sample is away from the null hypothesis

Question 16

Why would we use a t-test over a z-test?

Answer 16

When we don’t know the population std dev

Question 17

How do we estimate the population std dev in a t-test?

Answer 17

We use sample standard deviation

Question 18

Is the alpha level at a fixed 1.96 for a z-test or a t-test?

Answer 18

z-test

Question 19

How do we calculate degrees of freedom?

Answer 19

one less than our sample size (n-1)

Question 20

What are you testing for in an independent samples t-test?

Answer 20

Is there a difference in the results between the two groups?

Question 21

What are you testing for in a repeated measures design?

Answer 21

Has there been a change over time in the same sample?

Question 22

What is a correlational research design?

Answer 22

Correlational research is concerned with a relationship between two variables.

Question 23

What is a positive linear association?

Answer 23

High scores on x are related to high scores on y

Question 24

What is a negative linear association?

Answer 24

As scores on x increase, scores on y decrease

Question 25

What does Pearson's Correlation Coefficient measure? (r)

Answer 25

r measures the strength of the linear relationship between x and y The value of r lies between -1 and 1

Question 26

What r values will indicate a small, moderate, and strong effect respectively?

Answer 26

0.1, 0.3, 0.5