There are four main types of data; nominal and ordinal, which are categorical, and interval and ratio, which are numerical.
Nominal data consists of names categories that are inherently unordered. This data can be counted to calculate percentages but cannot be used to calculate averages. When there’s only two categories the data is referred to as dichotomous.
Ordinal data refers to the order of the values being measured. No category on an ordinal scale has a truly mathematical value, but they can be used to calculate percentages.
Interval data is numeric data that doesn’t have a meaningful zero point, in that zero doesn’t indicate the absence of the value being measured, e.g. 0:00am isn’t the absence of time and 0°C isn’t the absence of temperature.
Conversely, ratio data is numeric data in which the zero point is meaningful and does indicate an absence of the value, e.g. $0 and 0ml. This is evidenced in the chart below.