Question #1
This question is based on example #1 on slide 4 (page 54) of your course packet.
Furniture World is a manufacturer of office furniture. They have come out with a new
computer desk, and have asked their factory manager for a job design to get it produced.
She has narrowed it down to two possibilities; Design A
(population 1)
, and Design B
(population 2)
. She gathered samples of 25 for each design type. Data can be found
here
.
You can assume production time variances are equal.
Is either design quicker?
Note that this question is identical to example #1 on slide 14, page 44 of the course
packet.
What is the relevant point estimate?
.272 = 0.272
What is the value of the test statistic?
.9273 = 0.9273
This test statistic has
•
A standard normal distribution
•
A t distribution
•
A chisquared distribution
What is the pvalue for this test?
.35839 = 0.35839
Allowing for a 10% chance of a Type I error, what is your conclusion for this test?
•
Do not reject the null hypothesis and conclude that one design is quicker than
the other one.
•
Do not reject the null hypothesis; therefore, there is not enough evidence to
conclude that one design is quicker than the other one.
•
Reject the null hypothesis and conclude that one design is quicker than the
other one.
•
Reject the null hypothesis; therefore, there is not enough evidence to conclude
that one design is quicker than the other one.
Construct a 95% confidence interval for the difference in production time between design
A and design B.
Use the TINV function to get the tvalue. For help, look at pages 156 and 157 of the
course packet.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
So, just type =TINV(0.05, d.f.) in excel to get the tvalue you need.
The LCL and the UCL are:
.3176 = 0.3176
and
.8616 = 0.8616
Item 3:
You made all of the correct selections.
Item 6:
Your answer is within ±.0001 of the solution  correct.
Item 7:
Your answer is within ±.0001 of the solution  correct.
You received a raw score of 100% on this question.
Question #2
This question is based on exercise #2 on slide 17 (page 55) of your course packet.
A publisher is interested in the effects of sales of college texts that include more than 100
data files. The publisher plans to produce 20 texts in the business area, and randomly
selects 10 to have more than 100 data files. The remaining 10 are produced with at most
100 data files.
For those with more than 100, first year sales averaged 9254, and the sample standard
deviation was 2107. For the books with at most 100, average first year sales were 8167,
and the sample standard deviation was 1681.
Assuming the two populations are normal, with the same variance, test the null
hypothesis that the population means are equal against the alternative hypothesis that the
true mean is higher for books with more than 100 data files.
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '08
 Petry
 Normal Distribution, Null hypothesis, LCL, Student's tdistribution

Click to edit the document details