Here is a selection on resources for your further statistics training.

Day 1 - Data exploration and visualization

Bio-IT course: Introduction to R
Compact online course materials for data analysis in R, with a focus on tidyverse. Check out the upcoming Bio-IT courses to see when it is taught again.

R for Data Science
Online book by Hadley Wickham and Garrett Grolemund on data analysis in R using the tidyverse.

emblR
EMBL user club for R, offers interactive lessons and discussions on beginner and intermediate level R topics.

Day 2 - Probability distributions

Probability distributions are covered in almost any basic statistics book.

Day 3 - Statistical tests

CSDA hypothesis testing course from 2018
This hypothesis testing lecture was the basis for the slides of day 3.

MSMB chapter on testing
This online book chapter gives a didactic introduction on testing and multiple testing using biological examples.

Day 4 - Contingency tables

Agresti, A. (2006). An Introduction to Categorical Data Analysis: Second Edition. https://doi.org/10.1002/0470114754
This is a very comprehensive and well written book on categorical data analysis with many examples.

Day 4 - Multiple testing

MSMB chapter on testing
This online book chapter gives a didactic introduction on testing and multiple testing using biological examples.

How to interpret a p-value histogram
This blog on varianceexplained.org sums it up quite nicely.

General