Sampling

Question 1

What is a population

Answer 1

The whole set of items

Question 2

What is a census

Answer 2

A way to observe every member of a population

Question 3

What is a sample

Answer 3

A selection of observations taken from a subset of the population, to infer about the population

Question 4

What are the advantages to a census

Answer 4

Completely accurate

Question 5

What are the disadvantages to a census

Answer 5

Time consuming, expensive, hard to process large quantity of data

Question 6

What are the advantages to a sample

Answer 6

Less time consuming, cheap, less data to process

Question 7

What are the disadvantages to a sample

Answer 7

Data may not be accurate, sample may not be large enough

Question 8

What are sampling units

Answer 8

Individual units of a population

Question 9

What is a sampling frame

Answer 9

Where the sampling units of a population are named and numbered to form a list

Question 10

What are the types of sampling

Answer 10

Simple random, systematic, stratified, quota and opportunity sampling

Question 11

What is simple random sampling

Answer 11

Where every sampling unit has an equal chance to be chosen from a random number generator

Question 12

What is systematic sampling

Answer 12

The required sampling units are chosen at regular intervals from an ordered list

Question 13

What is stratified sampling

Answer 13

The population is divided into mutually exclusive strata and a random sample is taken from each, to represent the whole population

Question 14

What is quota sampling

Answer 14

The researcher selects a sample that reflects the characteristics of the whole population. Sizes of each sample from each strata is predetermined

Question 15

What is opportunity sampling

Answer 15

This consists of taking the sample from people who are available at the time of the study and who fit the criteria they are looking for

Question 16

+/- of simple random sampling

Answer 16

Free of bias, easy and cheap, equal chance of selection ——- Not suitable when population is large, sampling frame is needed

Question 17

+/- of systematic sampling

Answer 17

Simple and quick, suitable for large populations ——- Sampling frame is needed, can be biased if sampling frame is not random

Question 18

+/- of stratified sampling

Answer 18

Sample accurately reflects the population ——- population must be divided into distinct strata first, same disadvantages as random sampling in each strata

Question 19

+/- of quota sampling

Answer 19

No sampling frame required, quick and easy, easy comparison ——- non-random sampling so could be biased, non-responses are not recorded as such, population must be divided into groups

Question 20

+/- of opportunity sampling

Answer 20

Easy, inexpensive ——- unlikely to provide a representative sample, highly dependent on individual researcher