Task 5: Are you sure?

Question 1

Internal validity is ..

Answer 1

the ability of your research design to adequately test your hypotheses.

Question 2

Confounding happens when..

Answer 2

two or more variables combine in such way that their effects cannot be separated.

Question 3

The 7 threats to external validity:

Answer 3

1. History (event other than treatment)
2. Maturation (age or fatigue)
3. Testing (prior testing affects post-treatment testing)
4. Instrumentation (instrument calibration)
5. Statistical regression (extreme scores move closer to the mean)
6. Selection bias (subjects exposed to diff. treatments)
7. Experimental mortality (loss of subjects).

Question 4

You can only enhance the internal validity during the..

Answer 4

design phase of your study.

Question 5

External validity is..

Answer 5

the degree that the results of a study can be generalised beyond the limited research setting and sample they were obtained.

Question 6

Threats to external validity (4):

Answer 6

1- Reactive testing (pre-testing affects participants reaction)
2- Interactions between participant selection bias and the independent variable (effects only apply to participants)
3- Reactive effects of experimental arrangements (artificial experimental situations and participants knowledge that they are tested)
4- Multiple treatment interference (early + later treatment)

Question 7

The steps you take to increase one type of validity tend to ..

Answer 7

decrease the other.

Question 8

Research settings :

Answer 8

1- Laboratory setting

2- Field setting

Question 9

Characteristics of laboratory setting are:

Answer 9

• setting that is artificial relative to the natural environment ;
• researcher gains important control
• lose a degree of generality.

Question 10

The process of recreating the world in the laboratory is called

Answer 10

simulation. (observe -> identify -> reproduce)

Question 11

Characteristics of the field setting:

Answer 11

• experiment conducted in the participant’s natural environment ;
• high external validity
• low internal validity.

Question 12

Random sample:

Answer 12

every person in the population has an equal chance of being chosen for the study.

Question 13

Non-random sample:

Answer 13

usually individuals from a highly specialised subpopulation.

Question 14

Volunteer bias explains that..

Answer 14

a sample made up entirely of volunteers is biased, because the external validity of your experiment may be affected.

Question 15

What are the types of validity?

Answer 15

• Content (questions cover the range of behaviours)
• Construct (results agree with theory)
• Criterion-related (correlation = concurrent / predictive)

Question 16

A representative sample ..

Answer 16

closely matches the characteristics of the population.

Question 17

Biased sample..

Answer 17

a sample that is not representative of the population.

Question 18

What are the techniques of sampling?

Answer 18

• Simple random sampling
• Stratified sampling (dividing into segments, select a random sample from each segment)
• Proportionate sampling
• Systematic sample (every kth person)
• Cluster sampling (similar naturally occurring groups)
• Multistage sampling (large cluster + stratified)

Question 19

An economic sample is the one that includes..

Answer 19

enough participants to ensure a valid survey and no more.

Question 20

When considering the size of a sample, take into account:

Answer 20

the amount of acceptable error and the expected magnitude of the population proportions.

Question 21

A sampling error is the

Answer 21

deviation of sample characteristics from those of the population.