The rule of thumb doesn’t work that well to find a range for small data sets. Step 1: Find the standard deviation (e.g.Procedure for finding a standard deviation using the rule of thumb: What the rule of thumb tells you in most cases is that the bulk of the data can be found pretty close to the mean (within a couple of standard deviations) The result is that those erroneous “outliers” should have very little effect on your final statistic. It tells you how your data is clustered around the mean. The standard deviation is another measure of spread in statistics. The rule of thumb says that the range is about four times the standard deviation.

That’s why other measures of spread are sometimes preferred, like the mean. It’s an extremely high or low value that can throw off stats.

The score of 10 in the example above is what we call an outlier. That’s not a good reflection of your overall test performance at all. Assuming your highest score on another test was 94, then: Let’s say you had the flu one test day and scored a 10. The range only uses the smallest and the largest number in a set The rest of the values are ignored.

Step 2: Subtract the smallest number from the highest = 94 – 73 = 21. Step 1: Order your scores from smallest to largest: Problem: You take 7 statistics tests over the course of a semester. That’s how to find a range! Another Example of How to Find a Range Step 2: Subtract the smallest number in the set from the largest number in the set:Įxample question 2: What is the range of these integers?Įxample question 3: What is the range of the following times?Ģ.7 hrs, 8.3 hrs, 3.5 hrs, 5.1 hrs, 4.9 hrs Need help with a homework question? Check out our tutoring page!Įxample question 1: What is the range for the following set of numbers? 10, 99, 87, 45, 67, 43, 45, 33, 21, 7, 65, 98? The same two steps are used to find a range whether you are dealing with positive numbers, negative numbers, or time (e.g.

How to find a range in excel