Supplementary Exercises

Supplementary Exercises

Supplementary Exercises
(See related pages)

1.30

Some television stations attempt to gauge public opinion by posing a question on the air and asking viewers to call to give their opinions. Suppose that a particular television station asks viewers whether they support or oppose a proposed federal gun control law. Viewers are to call one of two 800 numbers to register support or opposition. When the results are tabulated, the station reports that 78 percent of those who called are opposed to the proposed law. What do you think of the sampling method used by the station? Do you think that the percentage of the entire population that opposes the proposed law is as high as the 78 percent of the sample that was opposed?

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0072977477/hm_logo_cmyk.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (K)</a>

1.31

In early 1995, The Milwaukee Sentinel, a morning newspaper in Milwaukee, Wisconsin, and The Milwaukee Journal, an afternoon newspaper, merged to form The Milwaukee Journal Sentinel. Several weeks after the merger, a Milwaukee television station, WITI-TV, conducted a telephone call-in survey asking whether viewers liked the new Journal Sentinel. The survey was “not scientific” because any viewer wishing to call in could do so.

On April 26, 1995, Tim Cuprisin, in his “Inside TV & Radio” column in the Journal Sentinel, wrote the following comment:

WE DIDN’T CALL: WITI-TV (Channel 6) did one of those polls—which they admit are unscientific—last week and found that 388 viewers like the new Journal Sentinel and 2,629 don’t like it.
We did our own unscientific poll on whether those Channel 6 surveys accurately reflect public opinion. The results: a full 100 percent of the respondents say absolutely, positively not.

Is Cuprisin’s comment justified? Write a short paragraph explaining your answer.

1.32

Table 1.11 gives the “35 best companies to work for” as rated on the Fortune magazine website on March 14, 2005. Use random numbers to select a random sample of 10 of these companies. Justify that your sample is random by carefully explaining how you obtained it. List the random numbers you used and show how they gave your random sample.

TABLE 1.11 Fortune’s 35 Best Companies to Work for in March 2005 (for Exercise 1.32)

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0072977477/0073191914_001_053.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (K)</a>

1.33

A bank wishes to study the amount of time it takes to complete a withdrawal transaction from one of its ATMs (automated teller machines). On a particular day, 63 withdrawal transactions are observed between 10 A.M. and noon. The time required to complete each transaction is given in Table 1.12. Figure 1.11 shows an Excel runs plot of the 63 transaction times. Do the transaction times seem to be in statistical control? Why or why not? ATMTime

TABLE 1.12 ATM Transaction Times (in Seconds) for 63 Withdrawals ATMTime

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=gif::::/sites/dl/free/0072977477/339821/1_33.gif','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (25.0K)</a>

FIGURE 1.11 Excel Runs Plot of ATM Transaction Times for Exercise 1.33

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0072977477/bow77477_0111.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (K)</a>

1.34

Figure 1.12 gives a runs plot of the Cleveland Indians’ winning percentages from 1915 (when the team was renamed as the “Indians”) to 2004. Many longtime Indians fans believe that the April 1959 trade of Rocky Colavito, a feared home-run hitter, for Detroit’s Harvey Kuehn, a good average hitter without exceptional power, sent the team into a decline that lasted more than 30 years. Does the runs plot provide any evidence to support this opinion? Why or why not?

FIGURE 1.12 Runs Plot of the Cleveland Indians’ Winning Percentages from 1915 through 2004 (for Exercise 1.34)

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0072977477/bow77477_0112.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (K)</a>

1.35

THE TRASH BAG CASE TrashBag

Recall that the company will carry out a 40-hour pilot production run of the new bags and will randomly select one bag each hour to be subjected to a breaking strength test.

Explain how the company can use random numbers to randomly select the times during the 40 hours of the pilot production run at which bags will be tested. Hint: Suppose that a randomly selected time will be determined to the nearest minute.
Use the following random numbers (obtained from Table 1.1) to select the times during the first five hours at which the first five bags to be tested will be taken from the production line: 61, 15, 64, 07, 86, 87, 57, 64, 66, 42, 59, 51.

MINITAB, Excel, and MegaStat for Statistics

In this book we use three types of software to carry out statistical analysis—MINITAB, Excel, and MegaStat. MINITAB is a computer package designed expressly for conducting statistical analysis. It is widely used at many colleges and universities, and in a large number of business organizations. Excel is, of course, a general purpose electronic spreadsheet program and analytical tool. The analysis ToolPak in Excel includes many procedures for performing various kinds of basic statistical analyses. MegaStat is an add-in package that is specifically designed for performing statistical analysis in the Excel spreadsheet environment. The principal advantage of Excel is that, because of its broad acceptance among students and professionals as a multipurpose analytical tool, it is both well known and widely available. The advantage of a special-purpose statistical software package like MINITAB is that it provides a far wider range of statistical procedures and it offers the experienced analyst a range of options to better control the analysis. The advantages of MegaStat include (1) its ability to perform a number of statistical calculations that are not automatically done by the procedures in the Excel ToolPak, and (2) features that make it easier to use than Excel for a wide variety of statistical analyses. In addition, the output obtained by using MegaStat is automatically placed in a standard Excel spreadsheet and can be edited by using any of the features in Excel. MegaStat can be copied from the CD-ROM included with this book. MINITAB, Excel, and MegaStat, through built-in functions, programming languages, and macros, offer almost limitless power. Here, we will limit our attention to procedures that are easily accessible via menus without resort to any special programming or advanced features.

Commonly used features of MINITAB, Excel, and MegaStat are presented in this chapter along with an initial application—to produce a time series or runs plot. You will find that the limited instructions included here, along with the built-in help features of all three software packages, will serve as a starting point from which you can discover a variety of other procedures and options. Much more detailed descriptions of MINITAB can be found in other sources, in particular in the manual Meet MINITAB: Release 14 for Windows. This manual is available in print and as a .pdf file, viewable using Adobe Acrobat Reader, on the MINITAB Inc. website (http://www.minitab.com/products/minitab/14/documentation/aspx). Similarly, there are a number of alternative reference materials for Microsoft Excel. Of course, an understanding of the related statistical concepts is essential to the effective use of any statistical software package.

The instructions in this book are based on MINITAB (Version 14) for Windows and Microsoft Excel 2003 as found in Microsoft Office 2003.

Supplementary Exercises 1.30, 1.32, 1.33, 1.34, 1.35

Instructor Edition

Student Edition

Log In

Notes

Log In

Log In
You must be a registered user to view the premium content in this website. If you already have a username and password, enter it below. If your textbook came with a card and this is your first visit to this site, you can use your registration code to register, or purchase access.
Username:
Password:
	Forgot your password?

Log In

Site Preferences	(Log out)

		Send mail as:

TA email:
Other email:

"Floating" navigation?
Drawer speed:

Notes		(What is this?)

Add a note
1.	(optional) Enter a note here:
2.	(optional) Select some text on the page (or do this before you open the "Notes" drawer).
3.	Highlighter Color:
4.

Search
Search for:
Search in:

Home > Chapter 1 > Supplementary Exercises

	Instructor Resources
		MH Homework Manager Book Preface Guided Tour Preview Chapters CPS by eInstruction

	Course-wide Content
		Excel Templates Data Sets Megastat Appendix Appendix A Appendix B Appendix C Appendix D Appendix E

	Instructor Resources
		Instructors Manual PowerPoint Presentation
	Quizzes
		Multiple Choice and Tr...
	More Resources
		PowerPoint Presentations Excel Templates Narrated Slides
	eBook
		Chapter Opener 1.1 Populations and Sa... 1.2 Sampling a Populat... 1.3 Sampling a Process 1.4 Ratio, Interval, O... 1.5 An Introduction to... Chapter Summary Glossary of Terms Supplementary Exerc... Appendix 1.1 Appendix 1.2 Appendix 1.3 Appendix 1.4