Stats 1- Data Collection

Question 1

Census definition

Answer 1

Observation of every member of a population

Question 2

Sample definition

Answer 2

A selection of observations taken from a subset of the population which is used to represent the population as a whole

Question 3

Sampling unit?

Answer 3

Individual units of the population being sampled

Question 4

Sampling frame

Answer 4

List/order of all the sampling units of a population

Question 5

Different types of sampling

Answer 5

• simple random
• stratified
• systematic

Question 6

Simple random sampling advantages and disadvantages

Answer 6

+) free of bias, easy + cheap for small populations, each sampling unit has equal and known chance of selection
-) not suitable for large population, sampling frame is needed

Question 7

Systematic sampling advantaged and disadvantages

Answer 7

+) simple + quick, suitable for large populations

-) a sample frame is needed, can introduce bias if sampling frame is not bias

Question 8

Stratified sampling advantages and disadvantages:

Answer 8

+) sample accurately reflects population structure, provides proportional representation
-) population must be clearly classified into distinct strata, random sampling within the stratum may provide non representative data