Topic 1: Sampling and Sampling Distributions Chapter 6 ...

[Pages:145]Topic 1 --- page 1

Topic 1: Sampling and Sampling Distributions Chapter 6

Objective: To draw inferences about population parameters on the basis of _______information.

In Economics 245 (Descriptive Statistics) we saw that statistics are largely applied to describing population parameters, and estimating or testing hypotheses about population characteristics.

Example: ? measures of _______ tendency, such as the population mean, median, and mode;

? measures of dispersion, such as the population variance, standard deviation, coefficient of variation.

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If all values of a population are k____, we can determine these parameters. But for many populations, there are m______ and time constraints to the act of gathering data from an entire population to determine the population parameter of interest. Hence, samples are taken to _______ the population parameters.

In Topic 1 we will explore how a sample is taken, and how the information generated from the sample can be applied.

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To deal with the issues of proper sampling, we must ask the following questions:

1) What are the most c___ efficient means of collecting samples that generate the best representation of the population?

2) How do we clearly d_______ sample information in the most useful manner?

3) How do we generate i________ about the population from sample summaries?

4) How a_______ are the inferences generated from sample information?

Sample Design

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To answer question #1, we must describe how sample data is collected. (i.e. describe the procedure or plan of action.)

Definition:

Sample Design: is a pre-determined p___ depicting how to collect a sample from a given population.

That is, before any data collection takes place, the researcher p____ how he or she will actually collect the data.

The primary objective of the sample design is to collect a sample that accurately r________ the population that one is trying to replicate by a sample.

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Ideally, the sample contains population "characteristics" in the same proportion or c____________.

Ex. Suppose some population contains a 6.5% unemployment rate. (Obtained from the Census).

The sample must contain 6.5 % unemployed.

Ex. 50% of the population is over 60 years old.

Want a sample that has 50% of the people surveyed over 60 years old.

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Eg. Income structure: 10% population are in a 50% income-tax bracket; 55% of population are in a 40% income-tax bracket; 35% of the population are in a ................
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