Measures Of Location And Spread Flashcards
advantages and dis advantages of census
advantages : results accurate
disadvantages: time consuming and expensive
hard to process large quantities of data
sample advantages and disadvantages
Adv: Less time consuming and
cheaper
fewer people have to respond
Less data needs to be processed
Disadv: Data may not be as accurate
Sample may not be large enough to give information about small subgroups of the population
Explain Simple random sampling
A simple random sample of size n is one where every sample of size n has an equal chance of being selected.
Advantages of simple random sampling and disadvantages
Advantages
Free of bias
Easy and cheap for small samples
and populations
Each sampling unit has a known and
equal chance of selection
Disadvantages
Not suitable for large samples and populations
Sampling frame needed
Systematic sampling definition
The required elements are chosen at regular intervals from an ordered list.
Method of systematic sampling
Take every k value
K=population size(N)/sample size(n)
Start at random item between 1 and k
Systematic sampling advantages and disadvantages
Advantages
simple and quick to use
Suitable for large samples
and large populations
Disadvantages
A sampling frame is needed
Bias introduced if sampling frame is not random
Stratified sampling method
Sample size (n) / population size(N)
What is stratifies sampling
Diving population into groups and simple random sample carried out
Advantages of stratified sampling
Reflects population structure
Proportional rep
Dis advantage pop must be clearly classified
Method of simple random sampling
In sampling from each item he identifying number use random number gegeragor
Quota sampling
Pop divided into groups due to characteristic set to try and reflect a group’s proportion. Interviewer selects the sampling units
Opportunity sample
People who are available at the time
