Terms

Question 1

What is a population

Answer 1

Whole set of items of interest

Question 2

What is a sample

Answer 2

A subset that represents the population

Question 3

What is a sampling frame ?

Answer 3

A list of samples

Question 4

Describe simple random sampling

Answer 4

Where every sample has an equal chance for selection
Advantages: every sample has an equal chance of being selected so there is no bias, it is cheap
Disadvantages: not suitable for large populations, sampling frame needed, can introduce bias if not

Question 5

Describe systematic samplimg

Answer 5

Elements are chosen at regular intervals , every k interval where k is population size / sample size
Advantages: simple and easy, suitable for large populations
Disadvantages: samplimg frame needed, can introduce bias if the sampling frame is not random

Question 6

Describe stratified sampling

Answer 6

Population are separated into strata (representative groups) them a random sample from each strata is take
Advantages: reflects population structure, proportional representation of groups in population
Disadvantages: population must be put into distinctive strata, sampling frame needed , not suitable for large populations

Question 7

Describe Quota sampling

Answer 7

Population divided into desired groups, a quota is set for each group to try and reflect it in the groups entire population
Advantages: Allow small sample to be representative of the population, No sampling frame required, relatively easy and inexpensive, allows for easy comparison between different groups in the population
Disadvantages: non-random may introduce bias, the population must be divided into groups which may be inaccurate and costly, Increasing the scope of survey increases time and expense, non-responses are recorder

Question 8

describe opportunity sampling

Answer 8

sample taken from available people at the time of study who meet the criteria

advantages: Easy to carry out, inexpensive
disadvantages: unlikely to provide a representative sample, highly dependant on individual researchers

Question 9

what is discrete data?

Answer 9

Can only hold specific values e.g. number of people

Question 10

What is continuous data?

Answer 10

Data that can take any value e.g. height

Question 11

What sampling method would be used for: testing lightbulbs produced in a factory in a daily batch

Answer 11

systematic sampling, more simple than random and sampling frame is known

Question 12

What sampling method would be used for: surveying consumer opinion on your new drink released in the UK

Answer 12

Quota sampling or opportunity sampling, no sample frame

Question 13

What sampling method would be used for: determining students favourite tv program in school that is representative

Answer 13

stratified sampling, representative and access to sample frame