Summary

This has been a fun chapter and it covered a lot of useful tools. First, we discussed frequencies, which are counts of every possible value, and how to create frequency tables. Then, we discussed percentages as an extension of frequency that describes how the counts affect the whole of the data.

We talked about percent change, which is how a single value changes. It will always have a starting value and an ending value and be told in terms of the starting value. It matters which value is which. With percent change, you can have positive and negative values that correspond to the value increasing or decreasing. Percent difference is not quite the same thing. It describes the objective difference between two values of equal importance. As such, it does not matter which value is which, and it cannot have a negative value.

Confidence intervals describe a range around the mean of your sample distribution. You are confident that the “true mean” of your population...