Book Image

CompTIA Data+: DAO-001 Certification Guide

By : Cameron Dodd
Book Image

CompTIA Data+: DAO-001 Certification Guide

By: Cameron Dodd

Overview of this book

The CompTIA Data+ certification exam not only helps validate a skill set required to enter one of the fastest-growing fields in the world, but also is starting to standardize the language and concepts within the field. However, there’s a lot of conflicting information and a lack of existing resources about the topics covered in this exam, and even professionals working in data analytics may need a study guide to help them pass on their first attempt. The CompTIA Data + (DAO-001) Certification Guide will give you a solid understanding of how to prepare, analyze, and report data for better insights. You’ll get an introduction to Data+ certification exam format to begin with, and then quickly dive into preparing data. You'll learn about collecting, cleaning, and processing data along with data wrangling and manipulation. As you progress, you’ll cover data analysis topics such as types of analysis, common techniques, hypothesis techniques, and statistical analysis, before tackling data reporting, common visualizations, and data governance. All the knowledge you've gained throughout the book will be tested with the mock tests that appear in the final chapters. By the end of this book, you’ll be ready to pass the Data+ exam with confidence and take the next step in your career.
Table of Contents (24 chapters)
Part 1: Preparing Data
Part 2: Analyzing Data
Part 3: Reporting Data
Part 4: Mock Exams

Understanding frequencies and percentages

Frequencies and percentages are some of the simplest descriptive statistics, but they are useful nonetheless. This is why they are commonly part of EDA. You get to know the exact makeup of a variable. They can be used in various ways, but are most often applied to a single variable to understand how it is composed. More often than not, this one variable is categorical, so this is a great tool for your qualitative variables.

It should be noted that these can be used for multiple variables at the same time, but how complex they are increases exponentially with every variable added.


We can throw around all the fancy terms we want, but at the end of the day, a frequency is just a count of occurrences. You are literally just counting how many times a specific value occurs within a variable. There are many ways to do this, depending on the data analysis tools you are using, but for this exam, you must calculate it by hand. The...