L1 Experimental Design and Hypothesis Testing

Question 1

How many are the steps in designing experiments?

Answer 1

Four

Question 2

What are they?

Answer 2

1. Formulate research questions or hypotheses.
2. Translate the research hypotheses into a set of treatment conditions.
3. Select an appropriate experimental design to test the different treatment conditions.
4. Record the response measure that you are interested in.

Question 3

What is independent variables (IV)?

Answer 3

Experimental or treatment variable. Test the IV

Question 4

What is dependent variable (DV)?

Answer 4

The measured or response variable. Measure the DV.

Question 5

What are the various types of IV?

Answer 5

1. Quantitative Variables
2. Qualitative Variables
3. Classification Variables

Question 6

What is quantitative variables?

Answer 6

Represents of variations in terms of amounts.

Question 7

What is an example of quantitative variables?

Answer 7

Amount of drug.

Question 8

What is qualitative variables?

Answer 8

Represents of variations in terms of kind or type.

Question 9

What is an example of quantitative variables?

Answer 9

Strategy.

Question 10

What is classification variables?

Answer 10

Represent variations that are intrinsic to the subjects of the experiment.

Question 11

What are the examples of classification variables?

Answer 11

IQ, age and gender.

Question 12

What is nuisance variables?

Answer 12

IV which, if left uncontrolled, could exert a systematic influence on the different treatment conditions.

Question 13

What are examples of nuisance variables?

Answer 13

Temperature, time of the day and nature of participants.

Question 14

What is a systematic influence?

Answer 14

One that affects your measured response variable, DV.

Question 15

If nuisance variable is not controlled, what it will become?

Answer 15

Confounding variable.

Question 16

What is one of the way to overcome nuisance variable, if it can’t be controlled?

Answer 16

Completely randomized design.

Question 17

What is completely randomized design?

Answer 17

Participants are randomly assigned to serve in one of the treatment conditions.

Question 18

What is another name for completely randomized design?

Answer 18

Between-groups design.

Question 19

What is randomized block design?

Answer 19

Treat a participant (subject) as a block, where the individual serves in all treatment conditions of an IV.

Question 20

What is another name for randomized block design?

Answer 20

Repeated-measures design or within-participants/within-subjects design.

Question 21

What is research hypothesis?

Answer 21

A general experimental statement about the assumed nature of the world. Broad statement tying together an IV to a DV.

Question 22

What is a statistical hypothesis?

Answer 22

A set of precise hypotheses about the parameters of the different treatment conditions.

Question 23

What are the two statistical hypotheses?

Answer 23

Null hypothesis, H0 and alternative hypothesis H1.

Question 24

What is the relationship between the two statistical hypotheses?

Answer 24

Mutually exclusive.

Question 25

What is the null hypothesis?

Answer 25

The hypothesis that is tested, typically gives the same value to the different populations: H0: μ1 = μ2 = μ3 = etc. No treatment effects in the population.

Question 26

What is the alternative hypothesis?

Answer 26

States that the values of the parameter in the different treatment populations are not all equal. H1: not all μs are equal.

Question 27

What are the principles in hypothesis testing?

Answer 27

1. You cannot prove anything. 2. You are always testing the null hypothesis. 3. You are always trying to find evidence against null hypothesis: reject H0 to accept H1.

Question 28

What is sample means?

Answer 28

The sample mean from a group of observations is an estimate of the population mean.

Question 29

What is the criteria for rejecting the null hypothesis?

Answer 29

The significance level and represented by α (alpha), typically used is 0.05.

Question 30

What are the two types of errors in hypothesis testing?

Answer 30

Type I error and Type II error.

Question 31

What is Type I error also known as?

Answer 31

False positive.

Question 32

What is Type I error?

Answer 32

Reject the null hypothesis and accept the alternative hypothesis when the null hypothesis shouldn’t be rejected.

Question 33

What is the error in committing Type I error?

Answer 33

The error comes from being too liberal in rejecting H0.

Question 34

What is Type II error also known as?

Answer 34

False negative.

Question 35

What is Type II error?

Answer 35

Fail to reject the null hypothesis and accept it when the null hypothesis should have been rejected and the alternative hypothesis is true.

Question 36

What is the error in committing Type II error?

Answer 36

The error comes from being too conservative in rejecting H0.