# Archives

### The Chi-Square Statistic

We have been talking about statistics, and how to understand the statistics piece of a research article. Today we will start looking at the most common statistical tests used in health-care research. We will not talk about how to do these tests. Instead we will focus on how and why these tests are used. […]

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### Why we use statistics

You’ve designed your study, recruited a sample and collected data. Maybe your study finds 20% of the women who gave birth at a birth center had at least a second degree tear, while 25% of the women who gave birth at a hospital had at least a second degree tear. The next question you need […]

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### Types of Studies

No doubt you’ve seen something like this hierarchy of studies from Duke University’s Introduction to Evidence-Based Practice site. In this hierarchy, the studies are classified by the type of sample used. Types of Samples In a case study or case report, the sample is one or two individuals who experienced something unusual or noteworthy. In a […]

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### Disparities

When we compare two populations and find a difference in a health outcome, we want to look more closely to determine if that outcome difference is due to a difference in health related characteristics or non-health related characteristics. When the difference is due to something other than health characteristics, the difference is considered a disparity. […]

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### Populations and Risk

Last time we talked about the difference between incidence and prevalence. Today, we will look at how we can use these descriptive measures to understand differences in risk. Remember from Monday that the population is the group of individuals you would like to learn about. As midwives, we are often interested in specific groups of […]

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### Understanding Data – the measure

We need to talk about what might be considered the “back end” of statistics. That is, how did the data come to be? Types of Observations Data is simply a collection of variables, grouped by observation. In health care, the observation is usually a “case” or a “person”. Researchers make each observation in a variety […]

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### Learning to Read Carefully

I ran into an infographic titled A Breakdown of Birth in the U.S.A. I wanted to like it, but the information on the poster is misleading. It does make a great little demonstration of how to learn to question what you read. If you haven’t opened the infographic yet, put it in a new window […]

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### Descriptive Statistics

Most of the research we are interested in as midwives is inferential – meaning we draw conclusions about a group of people based on the results. However, descriptive statistics are still very helpful. Descriptive statistics help us organize and summarize information. For example, the number of births attended by midwives is a descriptive statistic. We […]

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### Understanding Data – the variable

A big part of understanding the statistics in research is understanding what is behind the data. What the data actually is, and how you obtain the data determine the types of statistical tests you will use. If you have been reading research, you probably already have an idea about most of the terms we will […]

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### What is Statistics

When I first began to read original research papers, I would skim over the statistical part to get to the conclusions. I understood statistics enough to tell if group A and B were different, and since the rest didn’t make sense to me I skipped it. I’m a little wiser now, and have a strong […]

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