Sampling Flashcards
1
Q
Simple random sampling pros and cons
A
- free of bias
- easy and cheap
- each unit has equal chance of selection
- not suitable when sample size is large
- sampling frame is needed
2
Q
Systematic sampling pros and cons
A
- simple and quick
- suitable for large samples
- sampling frame needed
- can be biased if no sampling frame
3
Q
Stratified sampling pros and cons
A
- accurately represent population proportion
- population must be clearly classified into distinct strata
4
Q
Quota sampling pros and cons
A
- small sample can be representative
- no sampling frame needed
- easy and cheap
- biased
- must divided into groups which can be costly or invalid
5
Q
Opportunistic sampling pros and cons
A
- easy
- cheap
- unlikely to be representative
- dependent on researcher
6
Q
What does ‘tr’ mean in Daily Total Rainfall and what would one do with ‘tr’ entries to clean data set?
How would the estimate of mean be affected?
A
when rainfall < 0.05mm
use ‘0’
mean will be underestimated
7
Q
What to do with tr values in rainfall samples?
A
Replace with 0.05
