Types of data

Nominal data - unordered groups, e.g., male/female, left-handed/right-handed, …

Ordinal data - rank ordered; the difference between item numbered n and n+i does not tell you anything other than that one is ranked ahead of the other, e.g., Top 500 Universities, top 10 protocols in bytes, …

Interval data - continuous ranges mapped to some scale, without a clear zero

Ratio data - like interval data, but with a clear absolute zero value

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Transcript

There are a number of different types of data that we can be concerned with. Most typically, we're concerned with nominal data.  So we've got an unordered group: male and female, left-handed and right-handed, etc.  Or an ordinal type of data. Where we now have rank order. So the difference between item number N and N+i doesn't tell us anything other than one is ranked ahead of another.  But it gives us an order. So, if we look at the top five hundred universities, the top ten protocols in bytes, etc.  Just knowing can see the top ten protocols in bytes - we don't know what the relative differences are the amounts - we simply know that one is larger than the other.  We can also have interval data. Where we have continuous ranges map to some particular scale, but we don't have a clear zero. We can also think about ratio data - it's like the interval data, but now we have a clear absolute zero value.