27.02.2017 Views

SPA 3e_ Teachers Edition _ Ch 6

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

6<br />

Sampling Distributions<br />

Please read the Introduction to the Teacher’s <strong>Edition</strong>.<br />

It will help prepare you for teaching this course, as it<br />

includes a lot of helpful information and advice.<br />

The Big Picture<br />

This chapter focuses on sampling distributions. A sampling<br />

distribution describes the possible values of a statistic such<br />

as the sample mean x or the sample proportion p^ and how<br />

often they occur. Three characteristics of sampling distributions<br />

will be examined in detail: center, variability, and shape.<br />

These are the same three characteristics used in <strong>Ch</strong>apter 1<br />

to describe distributions of quantitative data. The mean and<br />

standard deviation measure the center and variability of<br />

sampling distributions. The shapes of sampling distributions<br />

will be described with the same terms in use since <strong>Ch</strong>apter 1:<br />

skewed left, skewed right, symmetric, mound-shaped, and a<br />

new term from <strong>Ch</strong>apter 5: approximately normal.<br />

The variables examined in this chapter are examples of<br />

random variables, which were introduced in <strong>Ch</strong>apter 5.<br />

The sample count X is a binomial random variable and<br />

is therefore discrete. The sample proportion p^ is closely<br />

related to the sample count X. Finally, the sample mean x<br />

is a continuous random variable.<br />

The process of making a conclusion about a population<br />

based on the data in a sample is called statistical inference.<br />

<strong>Ch</strong>apter 6 lays the foundation for the statistical inference<br />

techniques learned in <strong>Ch</strong>apters 7–10. <strong>Ch</strong>apter 6 describes<br />

the sampling distribution of a sample statistic when certain<br />

characteristics are known about a population. In future<br />

chapters, we will test claims and estimate population<br />

parameters using what we have learned about these sampling<br />

distributions, even when population characteristics<br />

are unknown.<br />

The sampling distribution of p^ , the sample proportion,<br />

and x, the sample mean, are of particular importance for<br />

<strong>Ch</strong>apters 7–9. In those chapters, the values of unknown<br />

population proportions and population means will be estimated,<br />

and claims about them will be tested. Furthermore,<br />

estimates will be made and claims will be tested about the<br />

difference in two proportions and the difference in two<br />

means.<br />

Pacing and Assignment Guide<br />

Day Lesson Learning Targets/Classroom Activities Suggested Assignment<br />

1 <strong>Ch</strong>. 6 Introduction Lesson 6.1 Activity: A penny for your thoughts? None<br />

2 6.1 What Is a Sampling<br />

Distribution?<br />

• Distinguish between a parameter and a statistic.<br />

• Create a sampling distribution using all possible samples from a<br />

small population.<br />

• Use the sampling distribution of a statistic to evaluate a claim<br />

about a parameter.<br />

1–15 odd, 19<br />

3 6.2 Introduction Lesson 6.2 Activity: How many craft sticks are in the bag? None<br />

4 6.2 Sampling<br />

Distributions: Center<br />

and Variability<br />

5 6.3 Sampling<br />

Distribution of a Sample<br />

Count (The Normal<br />

Approximation to the<br />

Binomial Distribution)<br />

• Determine if a statistic is an unbiased estimator of a population<br />

parameter.<br />

• Describe the relationship between sample size and the variability<br />

of a statistic.<br />

• Calculate the mean and the standard deviation of the sampling<br />

distribution of a sample count and interpret the standard<br />

deviation.<br />

• Determine if the sampling distribution of a sample count is<br />

approximately normal.<br />

• If appropriate, use the normal approximation to the binomial<br />

distribution to calculate probabilities involving a sample count.<br />

1–15 odd, 19<br />

1–15 odd, 19<br />

6-2<br />

C H A P T E R 6 • Sampling Distributions<br />

Starnes_<strong>3e</strong>_ATE_CH06_398-449_v3.indd 2<br />

11/01/17 3:51 PM

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!