Task 6

Question 1

Internal validity

Answer 1

The ability of a research design to adequately test one’s hypothesis

Question 2

History (Threat to internal validity)

Answer 2

When multiple observations are taken over time, specific events may occur between observations that affect the results

Question 3

Maturation

Answer 3

Performance change due to age or fatigue

Question 4

Testing (threat to internal validity)

Answer 4

Protesting participants before the actual study can desensitize them for the post treatment measure

Question 5

Instrumentation

Answer 5

Unobserved changes in criteria used by observers (e.g. they change what counts as “verbal aggression” when scoring behavior under two experimental conditions) or in instrument calibration (e.g. instrument recording activity of rats becomes more/less sensitive over time)

Question 6

Statistical regression

Answer 6

When participants have been selected based on extreme scores on some measure and their scores are measured again, they will be closer to the average in the population

Question 7

Experimental mortality

Answer 7

Differential loss of participants from groups in a study (e.g. a group exposed to difficult conditions is likely to lose its frustration-intolerant participants than one exposed to less difficult conditions)

Question 8

External validity

Answer 8

The degree to which a study’s results can be generalized beyond the limited research setting and sample in which they were obtained

Question 9

Reactive testing (threat to external validity)

Answer 9

When a pretest affects participants reaction to an experimental variable, making their responses unrepresentative of the general population

Question 10

Population

Answer 10

All individuals in a group

Question 11

Subpopulation

Answer 11

A part of the population that might be studied exclusively due to large cost or other factors

Question 12

Sample

Answer 12

A smaller number of individuals selected from a (sub-)population

Question 13

Probability sampling

Answer 13

The most widely used technique to acquire a sample for a survey, where each member of the population has a known probability of being in the sample; ideally every member of the population has an equal chance of being in the sample.

Question 14

Representative sample

Answer 14

Closely matches the characteristics of the whole population

Question 15

Random sampling

Answer 15

Every member of the population has an equal chance of appearing in the sample

Question 16

Simple random sampling (SRS)

Answer 16

Randomly selecting a certain number of individuals from the population

Question 17

Stratified sampling (SS)

Answer 17

One solution to the representativeness problem of SRS.

First, the population is divided into segments (STRATA)
Next, a random sample of equal size is selected from each stratum

Question 18

Proportionate sampling

Answer 18

A solution to the overrepresentation problem

In PS, the proportions of people in the population are reflected in the sample

Question 19

Systematic sampling (SYS)

Answer 19

Sampling every element after a random start

Question 20

Cluster sampling (CS)

Answer 20

Identifying naturally occurring groups of participants (clusters) and randomly selecting certain clusters;
Once the clusters have been selected, all participants within a cluster are surveyed.

(Basic sampling unit here is a group rather than an individual)

Question 21

Multistage sampling (MS)

Answer 21

A variant of cluster sampling where one first identifies large clusters and randomly selecting among them (stage 1)
From the selected clusters, one randomly selects individual elements (rather than all elements in the cluster)

Question 22

Sampling error

Answer 22

The extent to which the characteristics of the sample differ from those of the general population