S1 Flashcards
What are discrete variables and give an example?
All the possible values can be listed Examples: 1) Shoe Sizes 2) Number of goals a football team scores 3) Number On dice
What are continuous variables and give an example?
You cannot list all possible values. Examples: 1) Distance 2) Mass 3) Temperature 4) Speed
What is simple random sampling?
Every possible sample of a given size is equally likely to be selected
What is stratified sampling?
Ensure that all stras are samples. The numbers sampled in the various strata are proportional to the size of their populations
What is cluster sampling?
Sub groups of the population which are called clusters. Each cluster should be reasonably representative of the entire population.
What is systematic sampling?
If you were surveying telephone subscribers, you might select a number at random, say 66 and then sample the 66th name on every page.
What is Quota sampling?
Has to ask a certain amount of people who fit a certain criteria, for example 50 women and 50 men. The choice of who is sampled is then left up to the interviewer.
What is opportunity sampling?
Used when circumstances make a sample readily available.
What is a self-selecting sample?
A sampling is self-selected when those involved volunteer to take part, or are given the choice to participate or decline.
What are the different types of sampling techniques?
1) Simple Random Sampling
2) Stratified Sampling
3) Cluster Sampling
4) Systematic Sampling
5) Quota Sampling
6) Opportunity Sampling
7) Self-Selecting Sample
What is the mode?
Most frequent number
What is the median?
The middle number
What is the mean?
Average number. Add numbers up then divide by how many numbers there are.
What is the range?
Largest number - Smallest number
How do you work out the Mean absolute deviation
∑(absolute(x-mean) / n
