Statistical Sampling - Paper 3 - Topic 1 Flashcards
Define:
Population
The whole set of items that are of interest
Define:
Sample
Section of population used to represent the population
Define:
Census
Data collected from the entire population
Advantages and Disadvantages of
Collecting data using a census
+Very accurate
+No bias
-Time consuming
-Expensive
Advantages and Disadvantages of
Collecting data from a sample
+Cheap
+Quick
-Can be inaccurate
-Can be bias
Explain:
Simple Random Sampling
- Number a population
- Use a random lottery or number generator
- Pick however many numbers you need
Explain:
Systematic sampling
- Number a population
- Divide the population by the desired sample size
- Whatever the interval is, choose from the population
Explain:
Stratified sampling
- Divide population into groups based on their characteristics
- Number all in each group
- Use random sampling for each group
Explain:
Quota sampling
Choosing a sample based on characteristics
Explain:
Oppurtunity/Convencience sampling
Take sample from those available
Advantages and Disadvantages of
Simple Random Sampling
+No bias
+Easy and Cheap
-Not suitable for large population
-Sampling frame needed
Advantages and Disadvantages of
Systematic sampling
+Simple and Quick
+Suitable for large population
-Sampling frame needed
-Can introduce bias
Advantages and Disadvantages of
Stratified Sampling
+Each group is represented
+Increased precision
-Complex
-Misclassification can occur
Advantages and Disadvantages of
Quota sampling
+Easy to do
+Quick comparisons
-Can be bias
-As study size increases, more time and money is spent
Advantages and Disadvantages of
Oppurtunity/Convenience Sampling
+Easy to carry out
+Cheap
-Unlikely to represent population
-Dependent researcher
