When fitting a linear regression model is it necessary to have normally distributed variables? Let’s see. One of the most common questions asked by a researcher who wants to analyse… Read More »Linear regression: should dependent and independent variables be distributed normally?
Ronald Fisher was a genius, for someone the greatest after Darwin. It would be enough to go to his Wikipedia page to understand what a great work he has done.… Read More »How to write a report on a fitted mixed-effect model in a manuscript or in a thesis correctly?
Since I have dealt with statistics, one of the phrases that I heard most often is: “I’ve never understood anything about statistics”. Someone even exaggerated: “I hated statistics at University… Read More »Why is statistics that difficult? How to make it easier?
When you write a thesis, you almost always want to get the most out of your work: you want your thesis to be given the highest score; or you want… Read More »Thesis or PhD thesis: why is statistics so important?
When we analyze data, one of the main rules that we learned is that we should not interpret the main effects when their interaction is statistically significant. Actually this rule… Read More »When does it make sense to interpret the main effects in the presence of interaction?
Adjusting for covariates in a multivariate model is a common practice in both randomized (to increase the accuracy of estimates) and observational studies, in order to take into account a… Read More »Interpreting the effect of treatment: the difference between conditional and marginal models
Often as a biostatistician I am asked to explain Odds Ratios to people who do not know anything about statistics. And it is not an easy undertaking. There are many… Read More »Explaining Odds Ratios to non-statisticians
The methods used to manage outliers during data analysis are not always correctly applied. In this post we will try to understand how avoiding biased results or losing some information… Read More »Outliers in data analysis: keep them or remove them?
Analysis of variance with repeated measures (repeated measures ANOVA) is one of the most misused techniques. Many researchers, as soon as they see the group of patients measured several times,… Read More »Repeated Measures ANOVA: why it is (almost always) a wrong choice
In this post we will try to provide some tips on how a researcher could answer the fateful question: should I adjust or not the significance level for multiple testing?… Read More »Multiple testing: when should we adjust for multiplicity?