2022 Introduction to Statistics in Research Mitchell 2nd ed

I N T R O T O R E S E A R C H : D A T A V I S U A L I Z A T I O N & C O M M O N S T A T T E S T S

understand standard deviation first. Standard deviation measures the spread around the mean. The more widely spread the values are, the larger the standard deviation.

What is standard deviation? Standard deviation tells you how data values vary around the mean. A larger standard deviation means there's more variability in your data, while a smaller deviation means there's less variability. I'm going to show you the formula for standard deviation, but we are not going to work this by hand. Instead, I've made a video to show you how to use descriptive statistics in Excel, (in the next section below) which shows us all kinds of things.

s = sample standard deviation ∑ = sum of X = each value x̅ = sample mean n – number of values in the sample

Also, above the line is called the sum of squared deviations and below the line is sample size – 1.

Equation 2: Formula for calculating standard deviation

Keep these properties in mind: • Standard deviation is used to measure spread or dispersion around the mean of a data set. • Standard deviation is never negative. • The larger the standard deviation, the more variability in data. • Standard deviation is sensitive to outliers. Even a single outlier can raise the standard deviation and distort the picture of the spread.

If you are analyzing normally distributed data, to calculate data intervals, standard deviation can be used in conjunction with the mean.

Demonstrate descriptive statistics in Excel?

Descriptive statistics is the first step in your analytic journey. Some of this is reviewed from the sections above, and we can use the fictitious crime scene data to see how and what you get when you use the descriptive statistics in Excel.

Using the crime data, we can run the descriptive statistics in Excel.

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