Exercise 7-1 Q # 10 Number of faculty. the numbers of faculty at 32 randomly selected state-controlled colleges and universities with enrollment under 12,000 students are shown below. use these data to estimate the mean number of faculty at all state-controlled colleges and universities with enrollment under 12,000 with 92% confidence. assume . 211 384 396 211 224 337 395 121 356 621 367 408 515 280 289 180 431 176 318 836 203 374 224 121 412 134 539 471 638 425 159 324 Q # 14 Number of jobs. a sociologist found that in a sample of 50 retired men, the average number of jobs they had during their lifetimes was 7.2. the population standard deviation is 2.1. a. find the best point to estimate of the population men. b.find the 95 % confidence interval of the mean number of jobs. c.find the 99% confidence interval of the mean number of jobs. d. which is smaller? explain why. Q # 18 Day care tuition. a random sample of 50 four-year-olds attending day care centers provided a yearly tuition average of $3987 and the population standard deviation of $630. find the 90% confidence interval of the true mean. if a day care center were starting up and wanted to keep tuition low. what would be a reasonable amount to charge? Exercise 7-2 Q # 8 State Gasoline Taxes. a random sample of state gasoline taxes ( in cents ) is shown here for 12 states. use the data to estimate the true population mean gasoline tax with 90% confidence. does your interval contain the national average of 44.7 cents? 38.4 40.9 67 32.5 51.5 43.4 38 43.4 50.7 35.4 39.3 41.4 Q # 10 Dance Company Students. the number of students who belong to dance company at each of several randomly selected small universities is shown below. estimate the true population mean size of a university dance company with 99% confidence. 21 25 32 22 28 30 29 30 47 26 35 26 35 26 28 28 32 27 40 Exercise 7-3 Q # 6 Belief in haunted places. a random sample of 205 college students were asked if they believed that places could be haunted, and 65 responded yes. estimate the true proportion of college students who believed in the possibility of haunted places with 99% confidence. according to time magazine,37% of americans believe that places can be haunted. Q # 14 Fighting U.S hunger. in a poll of 1000 likely voters, 560 say that the united states spends too little on fighting hunger at home. find a 95% confidence interval for the true proportion of voters who feel this way. Exercise 8-2 Q # 4 Moviegoers. the average moviegoer sees 8.5 movies a year. a moviegoer is defined as a person who sees at least one movie in a theater in a 12 month period. a random sample of 40 moviegoers from a large university revealed that the average number of movies seen per person was 9.6. The population standard deviation is 3.2 movies. at the 0.05 level of significance, can it be concluded that this represents a difference from the national average? Q # 8 Salaries of government employees. the mean salary o ...

1. Exercise 7-1
Q # 10
Number of faculty. the numbers of faculty at 32 randomly
selected state-controlled colleges and universities with
enrollment under 12,000 students are shown below. use these
data to estimate the mean number of faculty at all state-
controlled colleges and universities with enrollment under
12,000 with 92% confidence. assume .
211
384
396
211
224
337
395
121
356
621
367
408
515
280
289
180
431
176
318
836
203
374
224
121
412
134

2. 539
471
638
425
159
324
Q # 14
Number of jobs. a sociologist found that in a sample of 50
retired men, the average number of jobs they had during their
lifetimes was 7.2. the population standard deviation is 2.1.
a. find the best point to estimate of the population men.
b.find the 95 % confidence interval of the mean number of jobs.
c.find the 99% confidence interval of the mean number of jobs.
d. which is smaller? explain why.
Q # 18
Day care tuition. a random sample of 50 four-year-olds
attending day care centers provided a yearly tuition average of
$3987 and the population standard deviation of $630. find the
90% confidence interval of the true mean. if a day care center
were starting up and wanted to keep tuition low. what would be
a reasonable amount to charge?
Exercise 7-2
Q # 8
State Gasoline Taxes. a random sample of state gasoline taxes (
in cents ) is shown here for 12 states. use the data to estimate
the true population mean gasoline tax with 90% confidence.
does your interval contain the national average of 44.7 cents?
38.4
40.9
67
32.5

3. 51.5
43.4
38
43.4
50.7
35.4
39.3
41.4
Q # 10
Dance Company Students. the number of students who belong to
dance company at each of several randomly selected small
universities is shown below. estimate the true population mean
size of a university dance company with 99% confidence.
21
25
32
22
28
30
29
30
47
26
35
26
35
26
28
28
32
27
40

4. Exercise 7-3
Q # 6
Belief in haunted places. a random sample of 205 college
students were asked if they believed that places could be
haunted, and 65 responded yes. estimate the true proportion of
college students who believed in the possibility of haunted
places with 99% confidence. according to time magazine,37% of
americans believe that places can be haunted.
Q # 14
Fighting U.S hunger. in a poll of 1000 likely voters, 560 say
that the united states spends too little on fighting hunger at
home. find a 95% confidence interval for the true proportion of
voters who feel this way.
Exercise 8-2
Q # 4
Moviegoers. the average moviegoer sees 8.5 movies a year. a
moviegoer is defined as a person who sees at least one movie in
a theater in a 12 month period. a random sample of 40
moviegoers from a large university revealed that the average
number of movies seen per person was 9.6. The population
standard deviation is 3.2 movies. at the 0.05 level of
significance, can it be concluded that this represents a
difference from the national average?
Q # 8
Salaries of government employees. the mean salary of federal
government employees on the general schedule is $59,593. the
average salary of 30 state employees who do similar work is
$58,800 with . at the 0.01 level of significance, can it be
concluded that state employees earn on average less than federal
employees?
Q # 12
Student expenditures. the average expenditure per student (
based on average daily attendance) for a certain school year was
$10,337 with a population standard deviation of $1560. a survey

5. for the next school year of 150 randomly selected students
resulted in a sample mean of $10,798. do these results indicates
that the average expenditure has changed? choose your own
level of significance.
Exercise 8-3
Q # 6
Park acreage. a state executive claims that the average number
of acres in western pennsylvania state parks is less that 2000
acres. a random sample of five parks is selected, and the number
of acres is shown. at , is there enough evidence to support the
claim?
959
1187
493
6249
541
Q # 14
Chocolate chip cookie calories. the average 1-ounce chocolate
chip cookie contains 110 calories. a random sample of 15
different brands of 1-ounce chocolate chip cookies resulted in
the following calorie amounts. at the , is there sufficient
evidence that the average calorie content is greater than 110
calories?
100
125
150
160
185
125
155
145
160
100
150
140
135

6. 120
110
Exercise 8-4
Q # 8
Female Physicians. the percentage of physicians who are women
is 27.9%. in a survey of physicians employed by a larger
university health system,45 of 120 randomly selected physicians
were women. is there sufficient evidence at the 0.05 level of
significance to conclude that the proportion of women
physicians at the university health system exceeds 27.9%?
Q # 18
Doctoral student's salaries. nationally, at least 60% of Ph.D.
Students have paid assistantship. a college dean feels that this is
not true in his state, so he randomly selected 50 Ph.D. Students
and finds that 26 have assistantships. at , is the dean correct?
Exercise 9-1
Q # 6
Teachers salaries. california and new york lead the list of
average teacher's salaries. the california yearly average is
$64,421 while teachers in new york make an average annual
salary of $62,332. random samples of 45 teachers from each
state yielded the following
California
New York
Sample mean
64,510
62,900
Population standard deviation
8,200
7,800
at is a difference in means of the salaries?

7. Q # 10
Home Prices. a real estate agent compares the selling prices of
homes in two municipalities in south western pennsylvania to
see if there is a difference. the results of the study are shown. is
there enough evidence to reject the claim that the average cost
of a home in both locations is the same? use .
Scott
Ligonier
$93,430*
$98,043*
$5602
$4731
35
40
Q # 16
Ages of College Students . the dean of students wants to see
whether there is a significant difference in ages of resident
students and commuting students. she selects a sample of 50
students from each group. the ages are shown here. at ,decide if
there is enough evidence to reject the claim of no difference in
the ages of the two groups. use the P-value method. assume and
Resident Students
22
25
27
23
27
28
26
24
25
20
26
24
27
26

8. 18
19
18
30
26
18
18
19
32
23
19
19
18
29
19
22
18
22
26
19
19
21
23
18
20
18
22
21
19
21
21
22
18
20
19
23

9. Commuter Students
18
20
19
18
22
25
24
35
23
18
23
22
28
25
20
24
26
30
22
22
22
21
18
20
19
26
35
19
19

10. 18
19
32
29
23
21
19
36
27
27
20
20
21
18
19
23
20
19
19
20
25
Exercise 9-3
Q # 2
Retention test scores. a sample of non-english majors at a
selected college was used in a study to see if the student
retained more from reading a 19th century novel or by writing it
in DVD form. each student was assigned one novel to read and a
different one to watch, and then they were given a 100-point
written quiz on each novel. the test results are shown below. at ,
can it be concluded that the book scores are higher than the

11. DVD scores?
Book
90
80
90
75
80
90
84
DVD
85
72
80
80
70
75
80
Q # 4
Obstacle course times. an obstacle course was set up on a
campus, and 10 volunteers were given a chance to complete it
while there were being time. they then sampled a new energy
drink and were given the opportunity to run the course again.
the before and after times in seconds are shown below. is there
sufficient evidence at to conclude that the students did better
the second time? discuss possible reasons for your results.
Student
1
2
3
4
5
6
7
8
Before
67

12. 72
80
70
78
82
69
75
After
68
70
76
65
75
78
65
68
Q # 10
A random sample of six music students played a short song, and
the number of mistakes each student made was recorded. after
they practiced the song 5 times, the number of mistakes each
student made was recorded. the data are shown. at , can it be
concluded that there was a decrease in the mean number of
mistakes?
Student
A
B
C
D
E
F
Before
10
6
8
8
13

13. 8
After
4
2
2
7
8
9
Exercise 9-4
Q # 4
Undergraduate financial aid. a study is conducted to determine
if the percent of women who receive financial aid in
undergraduate school is different from the percent of men who
receive financial aid in undergraduate school. a random sample
of undergraduates revealed these results. at , is there significant
evidence to reject the null hypothesis?
Women
Men
Sample Size
250
300
Number receiving aid
200
180
On March 10, 2013 at precisely 12:45 PM, I have met professor
Carlos Santos for an interview regarding his past position.
Santos was very helpful with me, as he have gave me more than
I asked for as an interviewer. Advices, guidelines, and
directions to find the right path on becoming a successful
individual in my field. Professor Santos have studied in
different fields in order to be the successful man, he first went
through accounting in the bachelors degree, after that he took
his MBA from university of Arizona in research marketing. Not
only that, Santos has also combined psychology with them to

14. understand people and become better in communication.
Through out the interview, he answered my questions with the
best answers he can give, and we have also discussed and talked
in depth.
When I asked Professor Santos if he was truly contended with
the majors he has picked, his answer was yes, because it all
depends on which path a student wants to take after graduation.
Santos seemed to have planned his studying career from the
beginning, where he went to accounting in order to know where
all the numbers in business came from. Second, he wanted to
get a masters degree in exploration of research marketing in
order to take advantage of his bachelors degree of accounting to
properly use the numbers in marketing. Last was the study of
phycology to have understand people well and their behavior.
Then I asked if he would recommend students to pursue the
same degree he got in, and the answers came back to it all
depends on what an individual wants. I understood that every
other person has his own ambitions and dreams.
Santos past position was a market researcher in a big firm, HP.
As he says, his position is very time consuming. He worked
anywhere from 12-14 hours a day. Santos also added that he
traveled a lot during the year, in fact, he used to spend 220 days
a year in hotel rooms instead of his own house. Anywhere from
2 to 3 weeks a months, he was out of the state he used to live in.
Santos told me that one of the main reasons that made him leave
his job was the fact the he was always away from family.
Although HP allowed him to have an in home office to work in,
he still had to leave home a lot. He said that it was fun at the
beginning of his career but after that it becomes very tiring and
boring. The worst times for him to travel was during the
summers, and the reason for that is because during the summer
many children are in the airports where they made the airport
process slower than it usually should be. Last he said that
culture is a very important in the reason for him leaving his job,

15. as he was Hispanic, family was very important to him and it was
a must to spend time with them.
The pros of santos’s job was the variety of companies that he
could work with. For instance, his project that he might be
working in was a smartphone, but 2 months later he might be
working with another company that sells cars such as Toyota.
There was always something new to work in through out the
years. The second thing that he admired with his position was
the people that he worked with, santos described them as the
leaders in their field. Working with people that was vey
successful made him work harder and harder to make the
company realize that he really fits in the place, and he that he
really want to be successful. We then jumped to the cons of his
position, the first thing he told me was the amount of travel.
Although going to many cool places such as eruope, asia, and
states, it was tiring. Santos also told me that one day he had
breakfast in Geneva, lunch in Paris, and dinner in Rome. That’s
how tiring the job was because of the places he had to go to
meet people in the business he was in. He insisted that it was
time comsuming and needed a lot of time management in order
to get the job done right. The second negative thing Santos
mentioned was the fact the he used to work very hard in the
project he was given; yet, he was not able to see how the whole
project was put together. For example, if he was to market a
product, he could not see how the whole product was put
together and the exposed to people. He just knew the part he
was assigned to do.
The interesting and motivating interview was about to come to
end, but before that I wanted to explore more about the business
world. I had a couple of questioned that I have previously
planned to ask, and they were about my field. Since Professor
Santos has worked many years in the business, I figured out the
he knew what strengths I needed to develop while I am still in

16. my college years. But before going to that, I would like to state
the things that made this interview very pleasant to me was the
fact the I could freely confess my weaknesses without worrying.
I have confessed to Professor Santos that I did poor in time
management, and since I am an international student and
English was not my first language, communication was a bit
struggle to me. He definitely advised me to practice time
management because it is one of the factors that determine
one’s success, and develop communication skills. I also was
curious in knowing if having the ability to speak more than one
language was an advantage. He agreed and he told me that
knowing more than a language always made things easier to
deal with. Santos has worked in many different countries, and
he tried very hard in learning multiple words from different
languages. He gave me an example of how many Europeans
have that advantage, because in Europe many countries teach
many different language in high school. So it made
communication in Europe very easy and convenient. Other
things I explored in the interview with professor Santos was the
courses that I needed to concentrate on while in college. He
absolutely guided me well in what courses I had to work hard
on.