Sampling and Sample Size + Ch9

Question 1

Sample

Answer 1

Subset of population

Question 2

Sample frame

Answer 2

Listing of population, from which you draw your sample

eg: McGill Students

Question 3

Sampling error

Answer 3

Difference between population and sample due to chance variation

Can be reduced by increasing sample size

Question 4

Accuracy depends on 2 components (RS)

Answer 4

Representativeness
Sample size

Question 5

Census vs Sample

Answer 5

Census asks everyone - more accurate
Sample asks subset - accuracy varies

Question 6

4 steps in a sampling process

Answer 6

1. Define population of interest
2. Identify sampling frame (if possible)
3. Select sampling method
4. Determine sample size

Question 7

2 types of sampling methods (PN)

Answer 7

Probability method
Non-probability method

Question 8

Probability method

Answer 8

Every element in the population has a known chance of being selected
More likely to be representative subset of the population
Allows you to calculate margin of error
Difficult + expensive

Question 9

Non-probability method

Answer 9

Chances of selection for the various elements in the population are unknown
Unlikely to be representative subset of the population
Cannot calculate margin of error
Cheap + Easy

Question 10

4 ways of probability sampling (SSSC)

Answer 10

Simple random
Systematic
Stratified
Cluster

Question 11

Simple random sampling

Answer 11

Probability of selection is the same for all members

Question 12

Systematic sampling

Answer 12

Order population randomly, select every nth member

Question 13

Stratified sampling

Answer 13

Create mutually exclusive & collectively exhaustive subsets then sample randomly from each

Question 14

Cluster sampling

Answer 14

Create mutually exclusive & collectively exhaustive subsets then randomly select subsets

Question 15

4 ways of non-probability sampling (CPQS)

Answer 15

Convenience
Purposive
Quota
Snowball

Question 16

Convenience sampling

Answer 16

Select participants who are easily accessible

Question 17

Purposive sampling

Answer 17

Select participants using research’s best judgement about representativeness

Question 18

Quota sampling

Answer 18

Select participants based on variables of interest

Question 19

Snowball sampling

Answer 19

Select initial participants in some manner; ask initial participants for referrals for more participants

Question 20

Skewed population

Answer 20

Distribution has a long tail on one end and a short tail on the other - leads to inaccurate results

Question 21

Surrogate measure

Answer 21

Some easily determined characteristic of each population member is used to help partition or separate the population members into their various subgroupings