Lesson One
Lesson
Introduction <br> You will often encounter data that is incomplete or in which people have made mistakes getting the data from reality onto the computer. <br> In this lesson, you will: Form an idea about what is messy data Learn strategies for recognizing some typical problems with data sets Use simple scanning techniques to identify missing and odd values Acknowledge how data presentation may affect analysis See how numeric codes sometimes stand in for “text” values Learn to verify whether suspicious values are correct — or at least plausible.