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SD Part 1


Lesson 2: SD vs. IQR

There are a couple different ways to measure the variation or “spread” in a data set: the standard deviation (which we also touched on in Module 1) and the interquartile range. In this lesson, we’ll break down how each of these works and find out when to use one over the other.

Lab: SD and IQR

In the same way that the different measures of center are more or less useful depending on the type of data, the standard deviation and the interquartile range can each be more or less effective with different data types. In this lab, we’ll use Excel formulas to calculate both, and we’ll explore why the IQR is more useful with skewed data.

The lab instructions can be downloaded as a PDF file here.

The data set for this lab can be viewed here. From the link, copy and paste all the data into a new worksheet in Excel Online.

(Note: This lab uses the same data set you used in the labs for the previous module.)

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Essential Mathematics for Data Analysis in Microsoft Excel

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