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The Difference between Standard Deviation and Standard Error

November 10th, 2023 by

Standard deviation and standard error are statistical concepts you probably learned well enough in Intro Stats to pass the test.  Conceptually, you understand them, yet the difference doesn’t make a whole lot of intuitive sense.

So in this article, let’s explore the difference between the two. We will look at an example, in the hopes of making these concepts more intuitive. You’ll also see why sample size has a big effect on standard error. (more…)


Issues in Coding Missing Values

October 11th, 2023 by

There’s no mincing words here. Missing values can cause problems for every statistician. That’s true for a lot of reasons, but it can start with simple issues of choices stage 1made when coding missing values in a data set. Here are a few examples.

Example 1: The Null License Plate

Researcher Joseph Tartaro thought it would be funny to get the following California vanity license plate: (more…)


Getting Started with Stata Tutorial #2: Stata Menus

August 11th, 2023 by

A great way to get started with Stata is using its menus.

The first part of this Tutorial Series introduced you to Stata’s windows.  You can now begin learning how to use Stata to work with data.

Across the top are 8 tabs: File, Edit, Data, Graphics, Statistics, User, Window, and Help.

Stata menu tabs

We will not go through every option within the Stata menus. Instead, we’ll highlight a few options to get you started. In this article, we’ll start with three of the most useful menus: File, Data, and Help, along with those helpful icons under the menus.

In our next article, we’ll look at two more: Graphics and Statistics.
(more…)


Member Training: Operationalizing Research Questions

July 31st, 2023 by

One of the hardest steps in any project is learning to ask the right research question!
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Get Started with Stata Tutorial #1: How Stata Windows Work

July 17th, 2023 by

So, you want to get started with Stata?stage 1

Good choice!

At The Analysis Factor we recommend first becoming proficient in one statistical software. Then once you’ve progressed up to learning Stage 3 skills, adding a second statistical software. Whether it’s your first, second, or 5th statistical software, Stata has a lot that makes it worth learning.

When I first started using Stata, I remember being confused by the variety of menus and windows, the strange syntax of the code, the way it handled datasets… and what the heck is a do file? (more…)


Two Types of Effect Size Statistic: Standardized and Unstandardized

June 26th, 2023 by

Effect size statistics are all the rage these days.

Journal editors are demanding them. Committees won’t pass dissertations without them.stage 1

But the reason to compute them is not just that someone wants them — they can truly help you understand your data analysis.

What Is an Effect Size Statistic?

regression coefficientWhen many of us hear “Effect Size Statistic,” we immediately think we need one of a few statistics: Eta-squared, Cohen’s d, R-squared.
And yes, these definitely qualify. But the concept of an effect size statistic is actually much broader. Here’s a description from a nice article on effect size statistics:

“… information about the magnitude and direction of the difference between two groups or the relationship between two variables.

– Joseph A. Durlak, “How to Select, Calculate, and Interpret Effect Sizes”

If you think about it, many familiar statistics fit this description. Regression coefficients give information about the magnitude and direction of the relationship between two variables. So do correlation coefficients. (more…)