Lesson 1

Answer “Build Your Skills” questions 4 to 6 on page 154. Answer

 

 

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In Try This 3 and Self-Check 3, you used a random sample from a population to make predictions about the entire population. How important do you think the size of the random sample is? Do you think a small sample or a large sample will give better information about the population? In the following activity, you will explore the effects of different sample sizes.

 

Try This 5

 

Open the activity Sample Size.

 

Set the population size to 1800 and the sample size to 5. Click the “Take Sample” button to take a sample of the population. (You don’t need the “Check True Values” or “New Population” buttons yet.)

 

Determine the proportion of objects that are defective.

 

Create a table similar to the one that follows and use information from Sample Size to complete the first line of the table.

 

Sample Size	Number Defective	Proportion Defective
5
10
20
50
100
150
200
300
500

 

Change the sample size to 10 and click “Take Sample” to complete the second line of the table.

 

Complete the remainder of the table using the same population.

1. Which sample size do you expect has a defective proportion closest to the defective proportion of the population? Explain your reasoning.

Click the “Check True Values” button and determine the actual proportion of defective objects from the population.

2. How does the true proportion of defective objects compare to the sample proportions?

Save your responses in your course folder.

 

Share 2

 

With a partner or in a group, discuss your findings from Try This 5. Then, complete the following questions.

1. Describe the pros and cons of a large sample size.
2. Describe the pros and cons of a small sample size.
3. Explain what size you feel is a good sample size for the population you used in Try This 5.

Record your shared responses in your course folder.