There are several definitions for the word "Primer". Here I refer to it as any reference, be it a textbook or article, that introduces basic concepts of a topic.
Data mining
An introduction to ROC analysis
Machine learning is way easier than it looks
Receiver Operating Characteristic Analysis: A Primer
Some Things Every Biologist Should Know about Machine Learning
What is a hidden Markov model? (In addition, check this out.)
Understanding SVD right down to the basics
Data mining algorithms in R
PCA for dummies
Bioinformatics
Ten Simple Rules for Reproducible Computational Research
A Quick Guide to Organizing Computational Biology Projects
Communicating with a lay audience about scientific subjects
Collection of published “guides” for bioinformaticians
The ten simple rule collection from PLOS Computational Biology.
RNA-Seq primer by Michele Busby.
Bioinformaticians
How Not to Be a Bioinformatician
Core services: Reward bioinformaticians
Statistics
Explaining Odds Ratios
Bayesian statistics for dummies
A series of blog posts on statistics
A biologist's guide to statistical thinking and analysis
BMJ Statistics Notes
A beginners guide to interpreting odds ratios, confidence intervals and p values
A Brief Introduction to Probability & Statistics
Experimental design
Biology
Error bars in experimental biology
Introduction to Confocal Microscopy
Flow Cytometry
ENCODE: the rough guide to the human genome
Long noncoding RNAs: the search for function
Somatic versus germinal mutation
Cre/lox breeding for dummies
Links
Educational papers from Nature Biotechnology and PLoS Computational Biology
On data visualisation
Explained Visually is an experiment in making hard ideas intuitive
My Twitter favourites
