Week 3

Question 1

What is a t-statistical test?

Answer 1

Statistical method to decide whether an observed difference in sample scores represents a “real” difference in the population…. vs. just sampling error

Question 2

How many groups are in a t-test?

Answer 2

2 groups

Question 3

2 groups is another way of saying…?

Answer 3

2 levels of 1 IV

Question 4

What does a t-test do?

Answer 4

Finds the difference between group means divided by the variability within the groups( standard error of the mean difference)

Question 5

The error in a standard error refers to…?

Answer 5

All sources of variability within a set of data

that cannot be explained by the independent variable.

Question 6

A within group variability with no variability is known as being ___ ?

Answer 6

A within group variability with no variability is known as being definitely different ?

Question 7

A within group variability with little bit of variability is known as ___ ?

Answer 7

A within group variability with little bit of variability is known as probably different

Question 8

A within group variability with larger amounts of variability is known as ___

Answer 8

A within group variability with larger amounts of variability is known as maybe not different

Question 9

When the variability between groups are not necessarily the same, it is called…?

Answer 9

When the variability between groups are not necessarily the same, it is called a differing variance

Question 10

What is a parametric statistics?

Answer 10

A branch of statistics which assumes that sample data comes from a population that follows a probability distribution based on a fixed set of parameters.

Question 11

What are some examples of a parametric statistics?

Answer 11

• t-Tests
• ANOVA
• ANCOVA
• Regression
• Correlation

Question 12

What are the basic assumptions for all parametric test?

Answer 12

• Samples are randomly drawn from populations
• Population is normally distributed
• Homogeneity of variance (roughly)
• Data from ratio or interval (i.e. continuous) scales

Question 13

What rarely happens, but one still needs to be careful with when samples are randomly drawn from populations?

Answer 13

Generalization

Question 14

What are the ways to test if the population is normally distributed?

Answer 14

• Statistically
• Graphically
• Common sense

Question 15

When is the homogeneity of variance especially important?

Answer 15

With unequal group sizes

Question 16

How is the homogeneity of variance tested?

Answer 16

Statistically

Question 17

What statistical test is used for the t-test?

Answer 17

Levene’s test

Question 18

What are the statistical hypotheses for the null hypothesis for a two-level design?

Answer 18

• The two population means are equal
• The hypothesis can be in a nondirectional format (not equal)
• Directional format (one is greater than the other)

Question 19

A two-tailed test uses a ___ hypothesis

Answer 19

A two-tailed test uses a nondirectional hypothesis

Question 20

A one-tailed test uses a ___ hypothesis

Answer 20

A one-tailed test uses a directional hypothesis

Question 21

A two tailed test has ___ statistical power compared to the one tailed test

Answer 21

A two tailed test has less statistical power compared to the one tailed test

Question 22

What are the two types of t-test?

Answer 22

• Independent/unpaired t-test

- Paired t-test

Question 23

What happens in an unpaired(independent) t-test?

Answer 23

Testing to see if there is a difference between 2 groups

Question 24

What kind of design is found in an unpaired t-test?

Answer 24

• Pretest-posttest design (compare change scores)

- Posttest only design

Question 25

What happens in a paired(dependent) t-test?

Answer 25

Testing to see if there is a difference between conditions in the same person

Question 26

What kind of design is found in a paired t-test?

Answer 26

• Difference scores or pretest-posttest

- Repeated measures design

Question 27

A repeated measures factor is an example of a ___

Answer 27

A repeated measures factor is an example of a within-subjects factor

Question 28

A non-repeated measures factor is an example of a ____ factor

Answer 28

A non-repeated measures factor is an example of a between-subjects factor