My last blog post was on the difference between Sensitivity, Specificity and the Positive Predictive Value. While showing that a positive test result can represent a low probability of actually having a trait or a disease, this example used the values of Sensitivity and Specificity as pre-known input. For established tests and measures they indeed […]
Visualizing Sensitivity and Specificity of a Test
In my university course on Psychological Assessment, I recently explained the different quality criteria of a test used for dichotomous decisions (yes/no, positive/negative, healthy/sick, …). A quite popular example in textbooks is the case of cancer screenings, where an untrained reader might be surprised by the low predictive value of a test. I created a […]
Serengeti Park
Today, I don’t have cherry blossoms for you. Just some animals from the Serengeti Park. You can find higher resolutions at my 500px profile.
Vagrant VM for starting a Rails project
This is something off-topic for this blog, but after spending several hours setting up an environment for developing and testing a Ruby on Rails project, I’d like to share my solution. I recently had an idea for a small web-project, for that I’d like to use Ruby on Rails. From previous attempts of using Rails, […]
“Statistics is in a mess.”
The Valley of Shit
Having only started my PhD studies a few months ago, I am still eager and highly motivated to finish what I have just started. However, first doubts on the topic and the quality of my work already came (and went again, luckily), so I could relate to this post on the Valley of Shit: The […]
Replicability, Data Quality and Bayesian Methods
On the About page I wrote, that I blog about things I come across while researching for my PhD. So, you may very well ask what this PhD is supposed to be about. For the interested reader — researchers and the uninitiated alike —, here is some overview on my current plans and research focus.
ASA statement on p-Values: Improving valid statistical reasoning
A lot of debate (and part of my thesis) revolve around replicability and the proper use of inferential methods. The American Statistical Association has now published a statement on the use and the interpretation of p-Values (freely available, yay). It includes six principles and how to handle p-Values. None of them are new in a theoretical […]
Scientific Hoaxes and Bad Academic Writing
A new case of scientific hoax, that happened six years ago, is currently circulating: Six years ago I submitted a paper for a panel, “On the Absence of Absences” that was to be part of an academic conference later that year—in August 2010. Then, and now, I had no idea what the phrase “absence of […]
Mixing up Standard Errors and Standard Deviations
Over at the Non Significance blog, the author describes the case of a paper that has some strange descriptive statistics: What surprised me were the tiny standard deviations for some of the Variable 1 and 2, especially in combination with the range given. In the blog post, the author outlines his approach to make sense […]