M - Statistics & Mechanics 1 - 1) Data collection Flashcards
1
Q
Definition of a population
A
The whole set of items that are of interest
2
Q
Definition, benefit and drawback of censuses
A
- Definition: an observation or measure of every member of a population
- Benefit: should give a completely accurate result
- Drawback: time consuming and expensive
3
Q
Definition, benefit and drawback of samples
A
- Definition: a subset of the population who are used to find out information about the population as a whole
- Benefit: less time consuming and expensive than censuses
- Drawback: the data may not be as accurate or generalisable
4
Q
Definition of a sampling frame
A
A named or numbered list of sampling units
5
Q
List of all sampling methods
A
Random:
- Simple random
- Systematic
- Stratified
Non-random:
- Quota
- Opportunity
6
Q
Definition, benefit and drawback of simple random sampling
A
- Definition: where every sample has an equal chance of being selected
- Benefit: free of bias
- Drawback: not suitable when the population or sample size is large
7
Q
Definition, benefit and drawback of systematic sampling
A
- Definition: sample is chosen at regular intervals from an ordered list
- Benefit: simple and quick to use
- Drawback: sampling frame is needed so may introduce bias if it’s not random
8
Q
Definition, benefit and drawback of stratified sampling
A
- Definition: population is divided into different strata and a random sample is taken from each
- Benefit: sample accurately and proportionately reflects the population structure and its groups
- Drawback: selection withing each stratum is not suitable when the population or sample size is large
9
Q
Formula for stratified sampling
A
Number sampled in stratum = (number in stratum ÷ number in population) × overall sample size
10
Q
Definition, benefit and drawback of quota sampling
A
- Definition: selecting a sample that reflects the characteristics of the whole population
- Benefit: allows a (even small) sample to be representative of the population
- Drawback: divided into groups so may introduce bias
11
Q
Definition, benefit and drawback of opportunity sampling
A
- Definition: taking the sample from people who are available at the time that fit the criteria being looked for
- Benefit: easy and inexpensive to carry out
- Drawback: unlikely to provide a representative sample
12
Q
List of all types of data
A
- Quantitative
- Qualitative
· - Continuous
- Variable
