Week 2: Measuring Variables, Sampling, Validity and Reliability

Question 1

Population

Answer 1

Everyone the results will eventually be related to.

Question 2

Sample

Answer 2

A segment of the population which has been selected to be used in the study.

Question 3

Sampling Frame

Answer 3

A list of people which will be sampled from.

Question 4

Statistic

Answer 4

Characteristic of the sample data.

e.g. sample mean, sample SD

Question 5

Parameter

Answer 5

A numeric characteristic of the population data.

Question 6

Sample error

Answer 6

An error which takes place when there is a difference between the value of the sample statistic and the value of the population parameter.

Question 7

Probability sampling

Answer 7

A way of sampling which ensures that your sample is representative of the population.

Helps overcome sampling bias.

Question 8

Simple random sampling

Answer 8

A probability sampling method where participants are selected at random. Each participant has an equal chance of being selected for the sample.

Question 9

Systematic random sampling

Answer 9

A probability sampling method in which participants are selected with a random starting point but with fixed, periodic intervals.

Question 10

Stratified random sampling

Answer 10

A probability sampling method in which the population if divided by different subpopulations (strata) then a random sample is taken from each group.

Question 11

Multi-stage cluster sampling

Answer 11

A probability sampling method in which the population is divided in subgroups, but samples are not necessarily taken from all subpopulations.

Question 12

Non-probability sampling

Answer 12

Not every member of the population has an equal chance of being included in the sample

Question 13

Convenience sampling

Answer 13

Non-probability sampling method.
A sample is taken from all available participants.
Pros: easy, inexpensive
Cons: no control over representatives, and bias

Question 14

Snowball sampling

Answer 14

Non-probability sampling method.

Involves collecting data from targeted members of the population, then asking those members to provide information/contacts for other members of the population.

Used to study hard populations

Question 15

Quota sampling

Answer 15

Sample groups are divided into subgroups and samples are selectively taken.
Non-probability equivalent of stratified random sampling.

Question 16

Purposive/judgement sampling

Answer 16

Non-probability sampling method.

Selecting individuals who meet criterion of study.

Question 17

Face Validity

Answer 17

on face-value this measure seems to relate to the construct

Question 18

content validity

Answer 18

captures the entire meaning (all elements of definition) of a construct

Question 19

Criterion validity

Answer 19

agrees with external source

Question 20

Concurrent validity

Answer 20

agrees with pre-existing “gold-standard” measure

Question 21

Predictive validity

Answer 21

agrees with future behaviour

Question 22

Constructive validity

Answer 22

how well multiple indicators relate to each other (consistent with theory)

Question 23

Convergent validity

Answer 23

Similar measures (or measures of theoretically related constructs) are related

Question 24

Divergent validity

Answer 24

Different measures (or measures of theoretically unrelated constructs) are unrelated

Question 25

Test-retest reliability

Answer 25

same questions given on two occasions and data correlated

Question 26

Split Half reliability

Answer 26

split questions in half and correlate data from two halves

Question 27

Conbach’s Alpha reliability

Answer 27

equivalent to average of all possible split-half reliabilities for that test with that sample

Question 28

Inter-rater reliability

Answer 28

checking for agreement between multiple raters or judges