I'll start at the very basics of statistics. This post will contain a few definitions and a few formulae, nothing too taxing as we're just setting the scene, so to speak. In statistics, we have two types of variable; a qualitative variable and a quantitative variable. The features of these are as follows:
- Qualitative: Non numeric. For example: gender, religion.
- Quantitative: Numeric. For example: bank balance, age. Can be either discrete of continuous.
- Discrete - Can only have particular numbers. Example: Family members (Only whole numbers)
- Continuous - Anything else. Example: Weight, height.
- Nominal Data - Categorised data that cannot be arranged into an order. Eye colour, for example. This data can be either mutually exclusive and/or exhaustive. It's usually qualitative.
- Mutually exclusive - Can only be included in one category. Only one eye colour for example.
- Exhaustive - The data must appear in at least one category.
- Gender is mutually exclusive and exhaustive.
- Ordinal Data - Data that can be arranged into some sort of order. Individuals can be compared with one another here because of rankings, however the distances between each piece of data has no meaning.
- Interval Data - Can tell differences between the distance of data, yet we still aren't able to say that 100 is twice 50.
- Ratio Data - Has a 0 point, e.g number of family members. Now we can say that a family of 4 members is twice as big as a family of 2.