Homework 6

Spatial Analysis, Spring 2001

due March 9 2001

1.

The CyperBromo Vacuum company is selling its new model of vacuum cleaner, the ReallySux, with the claim that it removes 92.5% of the dirt on a normal floor in standardized tests. You decide to take them to task, and use the ReallySux model in an accurate replication of their tests. You dump dirt on clean carpets 6 times ¹, vacuum up the mess, and measure the remaining dirt. Your tests produce the following results:

Run Percent removal

1 92

2 89

3 86

4 82

5 87

6 85

(a): State your null hypothesis to test that the CyperBromo removes at least 92.5% of the dirt.
(b): What is the level of confidence that you have that your results are lower than those claimed by CyperBromo?
(c): What is your confidence interval at $\alpha = .05$ ?
(d): Can you deny that CyperBromo's claims are true?

2.

You run another, more comprehensive set of tests on the ReallySux model. This time, your results are as such:

$\bar{x}$ : 89.7

s : 4.4

n : 66

Can CyperBromo's claims be supported with these results?

3.

Two (hypothetical) politicians, Senator Cush and Governer McBain, are running for a high ranking political office in a neighboring state. You survey 276 potential voters, with the following results:

Candidate Votes

Cush 127

McBain 121

Senator Cush is using these numbers to claim that he's the front-runner.

What is your confidence interval at $\alpha = .05$ for each candidate?
What is your level of confidence that Cush is really the front-runner?

About this document ...

Homework 6

This document was generated using the LaTeX2HTML translator Version 98.1 release (February 19th, 1998)

The command line arguments were:
latex2html -local_icons -split 0 homework6.

The translation was initiated by Paul Box on 2001-02-28

Footnotes

... times ¹: assume that you are starting from a clean carpet each time: I don't want to get into residual dirt from previous tests here...

Paul Box
2001-02-28