MGMT 650 Fall 2016 Problem Set 3(Last updated 9/19/2016)1. Confidence Interval:Compute a 95% confidence interval for the...
Get help with any kind of assignment - from a high school essay to a PhD dissertation
MGMT 650 Fall 2016 Problem Set 3
(Last updated 9/19/2016)
1. Confidence Interval:
Compute a 95% confidence interval for the population
mean, based on the sample numbers 21, 22, 33, 34, 25,
26, and 139.
Change the last value to 29 and re-compute the
confidence interval.
What is an outlier and how does it affect the confidence
interval?
2. Confidence Interval:
A sample from a normal population has size = 109
observations, mean = 7.99, and standard deviation =
3.67. What is the 95 percent confidence interval for the
population mean? Use the Excel function,
=CONFIDENCE.NORM() and the mean to find the two
limits.
3. Confidence Limit:
The director of admissions at the University of Maryland,
University College is concerned about the high cost of
textbooks for the students each semester. A sample of 25
students enrolled in the university indicates that x(bar) =
$315.40 and s = $43.20.
a. Using the .10 level of significance, is there evidence
that the population mean is above $300?
b. What is your answer if x(bar) = $315.40, s = $75.00,
and the level of significance is 0.05?
c. What is your answer if x(bar) = $305.11, s = $43.20,
and the level of significance is 0.10?
d. D. Based on the information in part a, what decision
should the director make about the books used for the
courses if the goal is to keep the cost below $300?
4. t-Test: Paired Two Sample for Means
In week 7 we will study Hypothesis Testing in detail.
For answering the following question, you need a brief idea of what
hypothesis testing is. Please read the following introduction:
http://www.socialresearchmethods.net/kb/hypothes.php
The director for Weight Watchers International wants to determine if
the changes in their program results in better weight loss. She
selected 25 Weight Watcher members at random and compared their
weight 6 months later to weight at the start of the program. Here are
the results: (The weight in the column labeled âAfterâ represents their
weights six months later and âBeforeâ represents their weight at the
start of the sixÂmonth period.) The director used .05 as the
significance level.
Use Excel to test H0: After â Before ? 0 vs. HA: After â Before < 0.
For each paired difference, compute After â Before. In Data Analysis,
tÂTest: Paired Two Sample for means, select the After data for
Variable 1 Range. Note that the critical value output by Data Analysis
for this test is always positive. In this problem, the sign of the critical
value is negative corresponding to a 1Âtailed test with lower reject
region and negative lower critical value. State your conclusion.
Perso
n
1
2
Befor
e
176
192
After
164
191
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
185
177
196
178
196
181
158
201
191
193
176
212
177
183
210
198
157
213
161
177
210
192
178
176
176
185
169
196
172
158
193
185
189
175
210
173
180
204
192
152
200
161
166
203
186
170
(Last updated 9/19/2016)
1. Confidence Interval:
Compute a 95% confidence interval for the population
mean, based on the sample numbers 21, 22, 33, 34, 25,
26, and 139.
Change the last value to 29 and re-compute the
confidence interval.
What is an outlier and how does it affect the confidence
interval?
2. Confidence Interval:
A sample from a normal population has size = 109
observations, mean = 7.99, and standard deviation =
3.67. What is the 95 percent confidence interval for the
population mean? Use the Excel function,
=CONFIDENCE.NORM() and the mean to find the two
limits.
3. Confidence Limit:
The director of admissions at the University of Maryland,
University College is concerned about the high cost of
textbooks for the students each semester. A sample of 25
students enrolled in the university indicates that x(bar) =
$315.40 and s = $43.20.
a. Using the .10 level of significance, is there evidence
that the population mean is above $300?
b. What is your answer if x(bar) = $315.40, s = $75.00,
and the level of significance is 0.05?
c. What is your answer if x(bar) = $305.11, s = $43.20,
and the level of significance is 0.10?
d. D. Based on the information in part a, what decision
should the director make about the books used for the
courses if the goal is to keep the cost below $300?
4. t-Test: Paired Two Sample for Means
In week 7 we will study Hypothesis Testing in detail.
For answering the following question, you need a brief idea of what
hypothesis testing is. Please read the following introduction:
http://www.socialresearchmethods.net/kb/hypothes.php
The director for Weight Watchers International wants to determine if
the changes in their program results in better weight loss. She
selected 25 Weight Watcher members at random and compared their
weight 6 months later to weight at the start of the program. Here are
the results: (The weight in the column labeled âAfterâ represents their
weights six months later and âBeforeâ represents their weight at the
start of the sixÂmonth period.) The director used .05 as the
significance level.
Use Excel to test H0: After â Before ? 0 vs. HA: After â Before < 0.
For each paired difference, compute After â Before. In Data Analysis,
tÂTest: Paired Two Sample for means, select the After data for
Variable 1 Range. Note that the critical value output by Data Analysis
for this test is always positive. In this problem, the sign of the critical
value is negative corresponding to a 1Âtailed test with lower reject
region and negative lower critical value. State your conclusion.
Perso
n
1
2
Befor
e
176
192
After
164
191
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
185
177
196
178
196
181
158
201
191
193
176
212
177
183
210
198
157
213
161
177
210
192
178
176
176
185
169
196
172
158
193
185
189
175
210
173
180
204
192
152
200
161
166
203
186
170
