Sarah-Jane O’Connor

University of Canterbury
Sarah-Jane is an ecologist who sometimes masquerades as a geneticist. Her statistical knowledge is embarassing in some social circles, but revered in others. Which probably just makes it neutral. She has a PhD in ecology from the University of Canterbury, NZ.

Articles by Sarah-Jane O’Connor

Time for T: How to Use the Student’s T-test

Time for T: How to Use the Student’s T-test

To pull together our discussions so far on hypothesis testing and p-values, we will use the t distribution as an example to see how it all works. The t distribution (you may have heard it called Student’s t) is a probability distribution that looks like a bell-shaped curve (or normal distribution). If we sample repeatedly from…

Pseudoreplication: Don’t Fall For This Simple Statistical Mistake

Pseudoreplication: Don’t Fall For This Simple Statistical Mistake

Now we come to the third part of our trifecta; in the last two posts I have gone over p-values and how they determine significance in null hypothesis testing, and we talked about degrees of freedom and their effect on the p-value. Finally, we come to pseudoreplication: where it can all go terribly wrong. Replication…

How Free is Your Degree?

How Free is Your Degree?

In the last post I talked about p-values and how we define significance in null hypothesis testing. P-values are inherently linked to degrees of freedom; a lack of knowledge about degrees of freedom invariably leads to poor experimental design, mistaken statistical tests and awkward questions from peer reviewers or conference attendees. Even if you think…

A Primer on Statistical Hypotheses

A Primer on Statistical Hypotheses

Hypothesis testing is the foundation around which we prove our science is worth funding, publishing and sitting through a conference presentation for. I can’t overstate the  importance of understanding hypothesis testing, such is the integral part it plays in biological analyses. The Null Hypothesis Fundamental to statistics is the concept of a null hypothesis, and…