1. Common data transformations
This chapter will take you through some basic techniques for working with numbers. To begin with, you'll learn how to perform some common transformations on numbers.
2. Caterpillar to butterfly
Here's a picture of a blue pansy transforming from a caterpillar to a butterfly. Your data transformations won't be as pretty, but the principle is the same. You transformations create things that are in the form you need them to be.
3. Logarithmic & exponential transformations (1)
If your data spans many orders of magnitude, that is it contains some values that are millions or billions of times larger or smaller than other values, then it can be useful to take logarithms of those values. The LOG10() function takes the base-10 log of your number. That is, it returns the number that you would have to raise 10 to the power of to get that number. To undo this log transformation, you can use the power of operator.
4. Logarithmic & exponential transformations (2)
For mathematical operations, particularly when dealing with lognormally distributed data there are two more helper functions. LN() takes the natural logarithm of a number, that is the logarithm with base e. The EXP() function undoes this, by calculating e to the power of that number.
5. Square root transformations
One other important transformation of numbers is the square root. This is commonly used when modeling count data. You can take a square root using the SQRT() function, and reverse it by raising the result to the power of 2.
6. Summary
In this video you learned that LOG10() and LN() perform log transformations, ten to the power x and EXP() perform exponential transforms, and SQRT() performs square root transformations.
7. Let's practice!
Time to transform some numbers!