Book Image

QlikView for Developers Cookbook

By : Stephen Redmond
Book Image

QlikView for Developers Cookbook

By: Stephen Redmond

Overview of this book

QlikView has been around since 1993, but has only really taken off in recent years as a leader in the in-memory BI space and, more recently, in the data discovery area. QlikView features the ability to consolidate relevant data from multiple sources into a single application, as well as an associative data model to allow you to explore the data to a way your brain works, state-of-the-art visualizations, dashboard, analysis and reports, and mobile data access. QlikView for Developers Cookbook builds on your initial training and experiences with QlikView to help you become a better developer. This book features plenty of hands-on examples of many challenging functions. Assuming a basic understanding of QlikView development, this book provides a range of step-by-step exercises to teach you different subjects to help build your QlikView developer expertise. From advanced charting and layout to set analysis; from advanced aggregations through to scripting, performance, and security, this book will cover all the areas that you need to know about. The recipes in this book will give you a lot of the information that you need to become an excellent QlikView developer.
Table of Contents (19 chapters)
QlikView for Developers Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Creating a control chart using Moving Range


Control charts are very quickly created by using a standard deviation function for control limits. However, Donald Wheeler, author of Understanding Variation: The Key to Managing Chaos, SPC Press, Inc., suggests that there are problems with standard deviation or standard error because of assumptions about the homogeneity of the data. Instead, he prefers a method using a moving average over an arbitrary period.

In this recipe, we are going to use the same set of rainfall data as the previous recipe, Creating a statistical control chart using standard deviation, to see how the rainfall data for Heathrow varies over time. Instead of using standard deviation of the data to derive the control limits, we will use the moving average (mR) and a statistical constant (2.66 – this value is obtained by dividing 3 by the sample size-specific d2 anti-biasing constant for a subgroup size of n=2).

We will use a 30-year period as our reference for what "Average"...