MINITAB Assignment 4 Fall 2015 100% Satisfaction Guarantees!

MINITAB Assignment 4
Fall 2015
Make sure you so the following:
1. Have your name on the document in the left hand corner
2. Put STAT100 under your name
3. Put MINITAB Assignment 4 centered on the page
4. Number and letter the answers accordingly
5. Copy and paste all generated graphics into your paper.
6. Use complete and coherent sentences to answer the questions.
7. Upload your MINITAB assignment on ELMS before the due date and time otherwise it is
considered late. Please use your name_MINITAB_4 as the file name. For example:
schimiak_MINITAB_4 or suechimiak_MINITAB_2 (make sure you save your document on your
computer or email it to yourself)
1. The heights were recorded for a Simple Random Sample of 270 freshmen. The mean of this
sample was 66.5 inches. The heights are known to be Normally Distributed with a population
standard deviation of 5.1 inches. Round answers to one decimal place. (You do not need a data
set for this problem.)
a. From the simple random sample of 270 freshmen heights:
i. Calculate the 96% Confidence Interval for the population mean height of a
freshman. Interpret the confidence interval. Use MINITAB to compute the
confidence interval. (Copy and paste the MINITAB output found in the Session
window after your answer.)
ii. Calculate the 87% Confidence Interval for the population mean height of a
freshman. Interpret the confidence interval. Use MINITAB to compute the
confidence interval. (Copy and paste the MINITAB output found in the Session
window after your answer.)
iii. As you increase the level of confidence, how will this affect the precision (i.e., the
width) of the interval? (Note: The smaller the interval, the more precise it is.)
iv. What sample size would you need for a 95% Confidence Interval to have margin of
error of no more than 0.45?
b. At a 0.05 significance level, test the claim that the average height of a freshman differs
from the 1956 average freshman height of 65.7 inches.
i. State the null and alternative hypotheses.
ii. State the significance level for this problem.
iii. State the test statistic. Use MINITAB to compute the test statistic and P-value. (Copy
and paste the MINITAB output found in the Session window after your answer. Use
this result to answer part (iv)).
iv. State the P-value.
v. State whether you reject or do not reject the null hypothesis.
vi. State your conclusion in context of the problem.
vii. If the true mean was 65.7 inches, did you make an error? If so, which error?
(Answer in complete sentences. You need to explain why or why not you made an
error as well as identifying the type of error (Type I or II) if you did make an error. DO

NOT answer these questions with a simple "Yes" or "No"; if you do, it will be marked
as incorrect.)

2. Sulfur compounds cause “off-odors” in wine, so winemakers want to know the odor threshold,
the lowest concentration of a compound that the human nose can detect. The odor threshold
for dimethyl sulfide (DMS) in trained wine tasters is about 25 micrograms per liter of wine (µg/l).
The untrained noses of consumers may be less sensitive, however. Here are the DMS odor
thresholds for 10 untrained students:
31 31 43 36 23 34 32 30 20 24
Assume that the odor threshold for untrained noses is Normally distributed with a population
standard deviation of 6.7 g/l.
Type the above data in column 1 in MINITAB worksheet and answer the following questions.
Round answers to one decimal place.
a. Calculate the 94% confidence interval for the mean DMS odor threshold among all
untrained students. Interpret the confidence interval. (Copy and paste the MINITAB
output found in the Session window after your answer.)
b. How large a sample is needed so that the margin of error is within 1.6 µg/l for a 95%
confidence level?
c. At a 0.05 significance level, test the claim that the mean threshold for untrained tasters is
greater than 25.1µg/l.
i. State the null and alternative hypotheses.
ii. State the significance level for this problem.
iii. State the test statistic. Use MINITAB to compute the test statistic and P-value. (Copy
and paste the MINITAB output found in the Session window after your answer. Also, use
this result to answer part (iv)).
iv. State the P-value.
v. State whether you reject or do not reject the null hypothesis.
vi. State your conclusion in context of the problem.
vii. If the true mean was 30.8 µg/l, did you make an error? If so, which error? (Remember
to answer in complete sentences. You need to explain why or why not you made an
error as well as identifying the type of error (Type I or II) if you did make an error. DO
NOT answer these questions with a simple "Yes" or "No"; if you do, it will be marked as
incorrect.)