Statistics Flashcards
Sampling Methods
Sampling methods come in several different ways including ones with bias and ones without bias.
Quota Sampling
- Quota Sampling involves dividing your samples based on groups e.g different Year groups or different store locations
Pros: Quick to Use and can designed around the investigation
Cons: Easily Biased/ Not Random
Opportunity
- Opportunity sampling involves taking a sample from those available to you e.g on the streets
Pros: Time and Place can be coinvent and related to the investigation
Cons: Very Unrepresentative and is not random
Judgement
- Judgement sampling is when the sampler makes their descions on who to sample e.g People with children
Pros: Quick and Adaptable to the Investigation
Cons: Unreliable, not random and requires a good judgement.
Cluster
- Choosing smaller groups from a larger group known as clusters, e.g Towns cities related to a counties data
Pros: Makes Data easier to understand, can be selected who is used.
Cons: Sample can easily be biased as well as can be unrepresentative of total population
Systematic
- A sample based on selecting the same item every x amount, usually production lines taking a quality control
Pros: Allows a consistent flow to make sure the overall item is good and is less biased
Cons: Requires a larger sample frame as well as must remain consistent throughout
Random
- Random Sampling is like the name suggests random, usually taken on number generators by assigning random numbers per member and selecting based off that.
Pros: Limited bias, very representative
Cons: May exclude key members, Impossible to be completely representative
Stratified
- Breaks down groups based on characteristics then randomly assigns samples based on that e.g year groups then random students. Aimed to be representative
Pros: Representative of each group of people and each characteristic
Cons: Time Consuming and relys on there being specific clear groups to split into
