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Unformatted text preview: Revised 01/19/2010 2201_Quiz2B.docm EXST 2201
Quiz 2B
Name: Section: Score: Directions: This quiz will be available on Moodle after the Chapter 6 lectures have been given.
Mark your answers on this printout. When the quiz is available on Moodle,
record your answers in the Moodle quiz and submit them for grading. You
may take the quiz only once and you will have an hour and a half to complete
it, so be sure of your answers before you start the Moodle quiz.
1. (Question 1 subparts below)
1A. What is the most appropriate situation for the ztest?
•
•
•
• Independent data
Distributed normally
Known population variance
All of the above. 1B. What is the magnitude of the critical value for a onetailed ztest with
significance 0.05?
•
•
•
• 2.48
1.65
1.96
0.54 1C. What is the magnitude of the critical value for a twotailed ztest with
significance 0.01?
•
•
•
• 2.33
1.65
1.96
2.58 1D. A sample of size 24 is collected, with sample average 47.1. If the population
standard deviation is 12, what is the value of the test statistic to test if the
population mean equals 50?
•
•
•
• –1.18
+1.65
+1.18
–1.65 Page 1 of 6 Revised 01/19/2010 2201_Quiz2B.docm 1E. A sample of size 24 is collected, with sample average 47.1. If the population
standard deviation is 12, what decision would be made to test that the
population mean equals 50 at significance 0.01?
•
•
•
• Reject the null.
Sometimes reject the null.
Reject the alternative.
Do not reject the null. 2. (subparts below)
2A. What is the most appropriate situation for the ttest?
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•
•
• s known, σ unknown
s unknown, σ unknown
µ known, σ known
µ unknown, σ known 2B. A sample of size 49 is collected, with sample average 107 and sample
standard deviation 34. What is the tvalue to test if the population mean
equals 100?
•
•
•
• –10.08
+10.08
–1.44
+1.44 2C. A sample of size 16 is collected. What is the magnitude of the critical value
for a onetailed ttest at significance 0.05?
•
•
•
• 1.746
1.753
6.314
2.131 2D. A sample of size 16 is collected, with sample average 77 and sample
standard deviation 7. What is the value of the test statistic to test if the
population mean equals 75?
•
•
•
• +4.571
+1.143
–5.803
–1.143 2E. A sample of size 16 is collected, with sample average 77 and sample
standard deviation 7. What decision would be made for a onetailed test
that the population mean equals 75 at significance 0.05?
•
•
•
• Do not reject the null.
Reject the null.
Sometimes reject the null.
Do not reject the alternative.
Page 2 of 6 Revised 01/19/2010 2201_Quiz2B.docm 3. Dioxin includes a group of chemicals produced from burning and some types
of manufacturing. The EPA uses 0.16 nanograms per cubic meter as its
screening level, which is set to protect against increased risks of cancer and
other adverse health effects. A manufacturer runs a plant and must shut down
if the dioxin levels are found to be above the screening level. The air at the
plant is appropriately sampled for several days. Does the manager have to
shut down the plant?
3A. What is the appropriate test procedure?
•
•
•
• zTest of the mean.
tTest of the mean.
zTest of the proportion.
None of these. 3B. What is the appropriate null hypothesis?
•
•
•
• µ = 0.16
µ ≤ 0.16
µ ≠ 0.16
µ ≥ 0.16 3C. What is the appropriate alternative hypothesis?
•
•
•
• µ = 0.16
µ < 0.16
µ ≠ 0.16
µ > 0.16 3D. Assume it should be a ztest. What decision would be made for a hypothesis
test at significance 0.05 if you calculated a test statistic of 1.94?
•
•
•
• Do not reject the null.
Reject the null.
Sometimes reject the null.
Do not reject the alternative. Page 3 of 6 Revised 01/19/2010 2201_Quiz2B.docm 4. A drug manufacturer states that the mean amount of Naproxen Sodium, the
active ingredient in reducing pain, in a tablet is 220 mg. A pharmacist wonders
if the mean amount of Naproxen Sodium is different from 220 mg? She
randomly selects 17 tablets, measures the amount of Naproxen Sodium in
each, and obtains the following information. Use significance 0.01.
Box plot
Normal probability plot
x
¯
s =
=
=
= All points inside fences.
All points inside bounds.
221.24 mg
2.42 mg 4A. What is the appropriate test procedure?
•
•
•
• zTest of the mean
tTest of the mean
zTest of the proportion
None of these 4B. What is the appropriate set of hypotheses (H0, H1)?
•
•
•
• µ = 220,
µ ≠ 220,
µ = 220,
µ = 220, µ ≠ 220
µ = 220
µ < 220
µ > 220 4C. What is the correct magnitude of the critical value?
•
•
•
• 2.583
2.921
2.235
2.120 4D. What is the correct value of the test statistic?
•
•
•
• –2.11
+2.11
+0.49
+8.43 4E. What is the correct Pvalue for this test statistic?
•
•
•
• 0.025
0.050
0.020
0.100 Page 4 of 6 Revised 01/19/2010 2201_Quiz2B.docm 4F. What is the correct confidence interval?
•
•
•
• (220.0, 222.4)
(219.2, 223.2)
(220.2, 222.2)
(219.5, 222.9) 4G. What is the correct conclusion of this hypothesis test?
•
•
•
• Do not reject the null.
Reject the null.
Sometimes reject the null.
Do not reject the alternative. 4H. Is the mean amount of Naproxen Sodium significantly different from 220 mg?
•
•
•
• Yes.
No.
Sometimes.
Depends on distribution. Page 5 of 6 Revised 01/19/2010 2201_Quiz2B.docm 5. (Question 5 subparts below)
5A. If you knew that the population mean was 50, which test would you use to
test a sample average of 57?
•
•
•
• zTest
tTest
pTest
None of these. 5B. A onetailed test of hypothesis was properly performed and the decision
was made to reject the null hypothesis at significance 0.05. Would the
same decision be made at significance 0.10?
•
•
•
• Yes.
No.
Sometimes.
Depends on distribution. 5C. A onetailed hypothesis test was properly performed and the decision
made to reject the null hypothesis at significance 0.05. Would the same
decision be made for a twotailed test?
•
•
•
• Yes.
No.
Sometimes.
Depends on distribution. 5D. A twotailed hypothesis test was properly performed and the decision
made to reject the null hypothesis at significance 0.05. Would the same
decision be made at significance 0.01?
•
•
•
• Yes.
No.
Sometimes.
Depends on distribution. 5E. What is the Pvalue for a critical value of 1.96?
•
•
•
• 0.050
Depends on number of tails.
0.025
Does not exist. 5F. What is the Pvalue for a test statistic of 1.96 for a onetail situation?
•
•
•
• 0.050
Depends on whether the test statistic is z or t.
0.025
Does not exist. Page 6 of 6 ...
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This note was uploaded on 05/20/2010 for the course EXST 2201 taught by Professor Mckenna during the Spring '08 term at LSU.
 Spring '08
 McKenna

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