Math 120
Chapter 3
Producing Data
Two methods of producing data are samples and experiments. In this chapter we will learn some fundamental facts about designing samples and experiments.
Experimental Design Video
This video will be shown in class. If you miss this class, the video is available in the library, either to sign out or to view in the library. The call number is QA 276.A63 1988 v.12 c.2.
When watching this video, or afterwards, try to answer the following questions:
______
v Why is the study of how lobsters behave not an experiment?
______
v In general, how does an experiment differ from an observational study?
______
v Who were the subjects in the Physicians' Health Study? What two treatments were compared?
______
v What is a placebo? What is the placebo effect? Why was it important to have a control group?
______
v Why were the subjects in the Physicians' Health Study assigned by chance to take either aspirin or a placebo?
______
v What are the advantages of making an experiment double blind?
Sampling Video
We will watch the last 10 minutes of this video in class. This video is also available in the library. The call number is QA 276.A63 1988 v.13 c.2.
The purpose of this video is to give you an idea of what sampling is and how it can be useful. In particular, notice the difference between a population and a sample.
v A population is the entire group of individuals that we want information about.
v A sample is a part of the population that we actually examine in order to gather information.
When watching this video, or afterwards, try to answer the following questions:
______
v In the sampling done on the truck, what is the population being sampled? What is the size of the population? The size of the sample?
______
v How many uses of sampling can you spot in the account of Frito-Lay chips? In each case, identify the population being sampled.
Samples and Surveys Video
This video will be shown in class. If you miss this class, the video is available in the library, either to sign out or to view in the library. The call number is QA 276.A63 1988 v.14 c.2.
When watching this video, or afterwards, try to answer the following questions:
______
v In the last video, we saw the difference between a population and a sample. What is the difference between a parameter and a statistic?
______
v What was the problem with the 1936 Literary Digest Poll? How was the sample selected for this poll? Why did it fail so badly to predict the election results?
______
v What is a simple random sample?
______
v What sort of thing can lead to sampling error? List as many factors as possible.
______
v What effect does the size of the sample have of the reliability of the results?
Math 120 Lecture Notes 27