The interquartile range is a measure of how disbursed your data is around a mean. It’s normally used in conjunction with the mean and median of a data set. There are several ways to find an interquartile range (the easiest of which is probably our interquartile range calculator). However, you can also calculate the IQR in Excel 2007.
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A histogram (or frequency distribution) is a type of graph that allows you to get a visual picture of your spread of data. While histograms are relatively easy to draw by hand, you’ll get a more professional result in Excel 2007.
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Random variables sometimes conform to a particular kind of distribution called a standard normal distribution. Most people will be familiar with the bell curve, probably because of high school grades or IQ tests. In general, grades in classes conform to the shape of a bell, with the majority of students falling into the center of the curve (C grades). Grades of F and A are smaller amounts of students at the tails of the bell. Graphing a standard normal distribution by hand can be tedious and time consuming. There are plenty of tools available that can assist students with visualizing a bell curve including graphing calculators (both online and purchased) and something that’s available on almost every computer: Microsoft Excel. Check your program list: if you have Microsoft Office installed (including Microsoft Word 2007), chances are you’ll also have Microsoft Excel 2007. Here’s how to graph a normal distribution in Excel in less than a minute.
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