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)
1
Part 1: Preparing Data
7
Part 2: Analyzing Data
13
Part 3: Reporting Data
19
Part 4: Mock Exams

Merging data

We will be covering all of the different ways to combine datasets. While it is nice when every variable you need is conveniently stored in one table or dataset, it doesn’t always happen. A large database will have several different tables and sometimes you need to compare two variables from two different tables, or you have part of a table stored in one part of the database and another month or year of the same table stored in another part of the database. There are many different ways to merge data, depending not only on the software or programing language you are using but also on how you need the tables to come together.

Key variables

Before we can jump in and talk about merging tables, we need to understand the concept of key variables. A key variable is simply a variable that is in both tables being merged, which allows all of the rows to be matched up in a way that makes sense.

Figure 5.1 – Customer names and customer locations

Figure 5.1 – Customer names and customer...