3.1 Experimental Design

Question 1

What are the seven steps to a good experimental design?

Answer 1

1. select population
2. operationalize the independent and dependent variable
3. carefully select experimental and control groups
4. randomly sample from the population
5. randomly assign individuals to groups
6. measure results
7. test hypothesis

Question 2

What are the two main objectives of the step “select population”?

Answer 2

1. determine population of interest
2. consider what group will be pragmatic to sample

Question 3

What are the three main objectives of the step “operationalize the independent and dependent variables”?

Answer 3

1. determine the independent and dependent variables
2. specify exactly what is meant by each variable
3. make sure dependent variable ca be measured quantitatively within the parameters of the study

Question 4

What are the two main objectives of the step “carefully select experimental and control groups”?

Answer 4

1. homogenize the two groups
2. isolate the treatment by controlling for potential extraneous variables

Question 5

What are the two main objectives of the step “randomly sample from the population?”

Answer 5

1. make sure all members of the population are represented
2. ideally each member has an equal chance of being selected

Question 6

What are the two main objectives of the step “randomly assign individuals to groups”?

Answer 6

1. individuals who have been sampled are equally likely to be assigned to either group
2. consider matching along potential extraneous variables which have been pre-selected

Question 7

What are the two main objectives of the step “measure the results”?

Answer 7

1. make sure measurements are standardized
2. make sure instruments are reliable

Question 8

What are the two main objectives to the step “test the hypothesis”?

Answer 8

1. use statistics to check for a significant difference
2. assign a pre-established threshold at which the null hypothesis will be rejected

Question 9

What is the independent variable?

Answer 9

variable manipulated by the research team

Question 10

What does it mean for an experiment to have reproducibility?

Answer 10

can be reproduced by other researchers

Question 11

What is the dependent variable?

Answer 11

variable the is measured

Question 12

What is the operational definition?

Answer 12

specification of precisely what the researchers mean by each variable

Question 13

What does quantitative and qualitative mean?

Answer 13

quantitative = numerical
qualitative = descriptive

Question 14

What is the experimental group?

Answer 14

group of participants receiving the treatment

Question 15

What is the control group?

Answer 15

group of participants that acts as a point of reference and comparison to the experimental group

Question 16

What are extraneous/confounding variables?

Answer 16

variables other than the treatment that could potentially explain an experimental result

Question 17

What is the placebo effect?

Answer 17

believing the treatment is being administered can lead to a measurable result

Question 18

What is a double blind study?

Answer 18

neither the person administering the treatment nor the participant truly knows if they are assigned to the experimental or control group

Question 19

What is the randomized blocking technique?

Answer 19

researchers evaluate where participants fall along the variables they wish to equalize across experimental and control groups and then randomly assign individuals from these groups

Question 20

What is reliability?

Answer 20

instruments produce stable and consistent results, measure what they are supposed to, and are replicable

Question 21

What is replicability?

Answer 21

repeated measurements lead to similar results