How to write Structured Query Language (SQL) code in R. Well there are many packages on CRAN that relate to databases. In the exercises below we cover some of the important data manipulation operations using SQL in R. We will use a ‘sqldf’ package, an R package for running SQL statements on data frames. Answers […]

## Select and Query Exercise

In this exercise we cover the basics on selecting and extracting data using queries. We add a few other materials into it. This should prepare you for the next exercise: Basic Decision Tree. The purpose of this is to give you the 20 percent of the tools to get 80 percent of work done. You […]

## Functions exercises vol. 2

[For this exercise, first write down your answer, without using R. Then, check your answer using R.] Answers to the exercises are available here. Exercise 1 Create a function that given a data frame and a vector, will add a the vector (if the vector length match with the rows number of the data frame) […]

## Bonus: Working with and visualizing a confidence interval

We just added this week’s set of bonus exercises! Bonus exercises are weekly exercises sets, available to subscribers to our weekly newsletter. Please sign up using the form on the right, and receive further details by email how to download the bonus exercises (and solutions, of course). This week’s bonus exercises focus on confidence intervals […]

## Descriptive Analytics-Part 5: Data Visualisation (Continuous variables)

Descriptive Analytics is the examination of data or content, usually manually performed, to answer the question “What happened?”. In order to be able to solve this set of exercises you should have solved the part 0, part 1, part 2,part 3, and part 4 of this series but also you should run this script which […]

## R Course Finder December update!

A few months ago we launched R course finder, an online directory that helps you to find the right R course quickly. With so many R courses available online, we thought it was a good idea to offer a tool that helps people to compare these courses, before they decide where to spend their valuable […]

## Model Evaluation Exercises 1

We are committed to bringing you 100% authentic exercise sets. We even try to include as different datasets as possible to give you an understanding of different problems. No more classifying Titanic dataset. R has tons of datasets in its library. This is to encourage you to try as many datasets as possible. We will […]

## Scripting Loops exercises Vol.2

[For this exercise, first write down your answer, without using R. Then, check your answer using R.] Answers to the exercises are available here. Exercise 1 Using the following variables: x=1 i=c(1:10) For this exercise, write a for() loop that increments x by two for each i. Exercise 2 Using the following variables: x=1 y=40 […]

## Frequency and chi-square test for independence Exercises

In this exercise, we cover some basics on frequency tables. We also briefly look at chi-square test for independence to find relationships of two variables. Before proceeding, it might be helpful to look over the help pages for the table, summary, and margin.table functions. Answers to the exercises are available here. If you obtained a […]

## Repeated measures ANOVA in R Exercises

One way, two way and n way ANOVA are used to test difference in means when we have one, two and n factor variables. A key assumption when performing these ANOVAs is that the measurements are independent. When we have repeated measures this assumption is violated, so we have to use repeated measures ANOVA. Repeated […]