Chapter-4 - What Can Go Wrong? Sampling and statistics seem...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 4 Sample Surveys in the Real World What Can Go Wrong? • Sampling and statistics seem simple, but many problems can arise. • Example: Prediction poll mistake of the 1948 presidential election that proclaimed Thomas Dewey as the winner over Harry Truman. Types of Errors • There are three types of errors that we will examine. These are ____________errors , ______________ error and ___________ errors. ______________________are errors caused by the act of selecting a sample. They cause sample results to be different from the results of a census. How Do Sampling Errors Happen? Improper sampling techniques are used. Sampling errors occur when some groups in the population are left out of the process of choosing the sample. Sampling Frame – list of individuals from which a sample is drawn. So if our sampling frame does not include everyone in the population, the sample will be biased. Random Sampling Error This results from chance selection in the simple random sample. – The error is due to chance. The best we can do to control this is to select a random sample. – ___________________includes only random sampling error Nonsampling Errors ______________________are errors not related to the act of selecting a sample from the population. They
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/07/2008 for the course STAT 110 taught by Professor Johnson during the Fall '07 term at South Carolina.

Page1 / 4

Chapter-4 - What Can Go Wrong? Sampling and statistics seem...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online