MSci_609_Sampling_distribution

MSci_609_Sampling_distribution - 2/5/2011 SAMPLING...

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
2/5/2011 1 SAMPLING DISTRIBUTION INSTRUCTOR: AMER OBEIDI Suppose you’re interested in the average amount of money that students in this class (the population) 2 have on them. How would you find out?
Background image of page 1

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

View Full DocumentRight Arrow Icon
2/5/2011 2 In January 2006, the New York Times asked half of the 1229 adults U.S. in their sample the following 3 question: •53% After 9/11, President Bush authorized government wiretaps on some phone calls in the U.S. without getting court warrants, saying this was necessary to reduce the threat of terrorism. Do you approve or disapprove. •46% After 9/11, President Bush authorized government wiretaps on some phone calls in the U.S. without getting court warrants. Do you approve or disapprove. 4
Background image of page 2
2/5/2011 3 Zogby International Zogby International is constantly searching, testing and measuring hypotheses and principles on 5 polling and public opinion research. Working with a panel of psychologists, sociologists, computer experts, linguists, political scientists, economists, and mathematicians, we explore every nuance in language and test new methods in public opinion research. It is this investment in time and money for research and development that makes us a leader in the public opinion field. Harris/Decima Ipsos-Reid Nanos Research Why bother determining the right sample size? Wouldn’t it be better to just include everyone and 6 Wouldn t it be better to just include everyone and “sample” the entire population? Such a special sample is called a census.
Background image of page 3

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

View Full DocumentRight Arrow Icon
2/5/2011 4 The physical impossibility of checking all items in the population. 7 The cost of studying all the items in a population. The sample results are usually adequate. Contacting the whole population would often be time-consuming. The destructive nature of certain tests The destructive nature of certain tests. 8
Background image of page 4
2/5/2011 5 Sample frame: the set of all sampling units (i.e., members, people) that have a chance to be selected. 9 A sample can only be representative of the population in the sample frame.
Background image of page 5

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

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 17

MSci_609_Sampling_distribution - 2/5/2011 SAMPLING...

This preview shows document pages 1 - 6. Sign up to view the full document.

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