Exam 2 (covers Chapters 6 and 7), Math 140 Spring 2015, CSUN Show All Work! Name:___________________________ Seat number:________________________ P a p e r s w i t h o u t n a m e / s e a t n u m b e r w o u l d l o s e 1 0 p o i n t s . Write your name and seat number now. For full credit, draw a sketch for each problem put all information on the graph. Problems 1 and 2 each 10 points, problem 3 has 15 points, problems 4-8 each 13 points. 1. Assume that weights of men are normally distributed with a mean of 172 lb and a standard deviation of 29 lb. Find the probability that if an individual man is randomly selected, his weight will be greater than 180 lb. 2. Birth weights in Los Angeles are normally distributed with a mean of 3400 grams and a standard deviation of 450 grams. If a hospital plans to set up special observation conditions for the lightest 4% of the babies, what weight is used to separating the lightest 4% from the others? 2 3. An airline jet has doors with a height of 70 inches. Heights of men are normally distributed with a mean of 69.0 inches and a standard deviation of 2.8 inches. a. If a male passenger is randomly selected, find the probability that he can fit through the doorways without bending. b. Find the probability that the mean height of the 28 men passengers is less than 70 inches. 3 4. In a study, 414 randomly selected CSUN students were asked whether they are willing to take a class at 7:00AM, 45% of them said that they are in favor. Find a 99% confidence interval estimate of the percentage of CSUN students who are in favor of having a class starting at 7:00AM. Can we safely conclude that the majority of CSUN students are in favor of having a starting at 7:00AM? Explain why or why not? 4 5. How many randomly selected students at CSUN must be surveyed to estimate the percentage of CSUNers who have a cellphone? Assume that we want to be 99% confident that the sample percentage is within two points of the true population percentage. Also, assume that it is estimated that 77% of students at CSUN have a cellphone 5 6. In a survey at CSUN, a simple random sample of 41 students has a mean family income $49,000. Assuming that population standard deviation is known to be $12,500, find a 95% confidence interval estimate of the mean family income of all CSUN students. 6 7. Assume that heights of students taking statistics are normally distributed. Listed below are the heights of 10 students from our Math 140 class that are selected randomly. Construct a 99% confidence interval estimate of mean of heights for all statistics’ students at CSUN. 63, 70, 64, 67, 62, 65, 64, 61, 69, 74. Explain the confidence interval in words. 7 8. The listed v ...

1. Exam 2 (covers Chapters 6 and 7), Math 140
Spring 2015, CSUN
Show All Work!
Name:___________________________
Seat number:________________________
P a p e r s w i t h o u t n a m e / s e a t n u m b e r w o u l d l
o s e 1 0 p o i n t s . Write your name and seat number now.
For full credit, draw a sketch for each problem put all
information on the graph.
Problems 1 and 2 each 10 points, problem 3 has 15 points,
problems 4-8 each 13 points.
1. Assume that weights of men are normally distributed with a
mean of 172 lb and a standard deviation of 29
lb. Find the probability that if an individual man is randomly
selected, his weight will be greater than 180
lb.
2. Birth weights in Los Angeles are normally distributed with a
mean of 3400 grams and a standard deviation
of 450 grams. If a hospital plans to set up special observation
conditions for the lightest 4% of the babies,
what weight is used to separating the lightest 4% from the
others?

2. 2
3. An airline jet has doors with a height of 70 inches. Heights
of men are normally distributed with a mean of
69.0 inches and a standard deviation of 2.8 inches.
a. If a male passenger is randomly selected, find the probability
that he can fit through the doorways
without bending.
b. Find the probability that the mean height of the 28 men
passengers is less than 70 inches.

3. 3
4. In a study, 414 randomly selected CSUN students were asked
whether they are willing to take a class at
7:00AM, 45% of them said that they are in favor. Find a 99%
confidence interval estimate of the
percentage of CSUN students who are in favor of having a class
starting at 7:00AM. Can we safely
conclude that the majority of CSUN students are in favor of
having a starting at 7:00AM? Explain why or
why not?

5. 4
5. How many randomly selected students at CSUN must be
surveyed to estimate the percentage of CSUNers
who have a cellphone? Assume that we want to be 99%
confident that the sample percentage is within two
points of the true population percentage. Also, assume that it is
estimated that 77% of students at CSUN
have a cellphone
5
6. In a survey at CSUN, a simple random sample of 41 students
has a mean family income $49,000.
Assuming that population standard deviation is known to be
$12,500, find a 95% confidence interval
estimate of the mean family income of all CSUN students.
6
7. Assume that heights of students taking statistics are normally
distributed. Listed below are the heights of
10 students from our Math 140 class that are selected randomly.
Construct a 99% confidence interval
estimate of mean of heights for all statistics’ students at CSUN.
63, 70, 64, 67, 62, 65, 64, 61, 69, 74.

6. Explain the confidence interval in words.
7
8. The listed values are waiting times (in minutes) of students at
Admission Offices at start of Fall semester,
where students enter a single waiting line that feeds three teller
windows. Construct a 99% confidence
interval for the population standard deviation σ. Data are 6.5,
6.6, 4.3, 7.2, 7.5, 6.5, 7.7, 6.8, 7.1, 4.4, 4.6
Alfrdan
Ali Alfrdan
Professor Cassady
Core 115 – Formal Paper # 2 First Draft
3/21/2015
Worker Profile
Have you ever find a person vocation and job like
your dream job and your vocation? Not only that, also your
cousin and your life experience adviser? To begin with, I’m
going to interview my cousin. His first name is Hashim, and his
last name is Alshurafa. Hashim is great hand ball, track and
field player, and a wonderful surgeon. He is one of my models
because I see him kind of super hero. Furthermore, hashim knew
how to manage his time well, so he made a balance of all his
vocation in successes way. Moreover he giving me a lot of
advice when I need, also my vocation as his vocation, so I’m

7. trying to follow his steps and his rule. Also I like his job and
vocation because I’m an athletic like him, but my sport areas in
Track and field is a race walking, and I have my achievement in
that’s area such as, I’m the fastest person in K.S.A in race
walking, so the Saudi race walk record under my name, and I
got a bronze medal In Arabian championship, and I did the limit
to enroll in world cup of race walking. Moreover, because I
have a renal transplantation, I would love to be a nephrology
doctor as Hashim. In addition, all his steps of education very
doctors should follow it. No doctor can be consultant before he
/she do those step. My plan to do as what Hasim did or any
doctor are the following:-
First of all, studying 4 years any major with premed
requirements, many volunteer in health field, The Medical
College Admission Test. Secondly, study 4 years in medical
school. 2years learning by attending lectures while other 2 years
are clinically. Thirdly we have to apply for the doctoral
reticently in internal medicine for 3 years and get the internal
medicine specialist license as what hashim did. Final step we
have to apply for fellowship in Nephrology that’s take 2 years
and then a short lessen and practice in 1 year of transplantation.
Hashim studied his Elementary school in in his hometown
Safwa which call Imam Ali Bin Abi Talib Elementry School
then he went to University of Toronto to study Kinesiology and
Premed there. After that, he was studying his Internal Medicine
degree in Saskatoon University and reticently of Royal
University Hospital in Saskatchewan, Canada. Then he went to
London Ontario to study and practice his fellowship in
Nephrology consultant degree in Western Ontario University,
also he worked as a fellowship student in London Health
Sciences Hospital. After he graduate, he worked in Saudi Arabia
King Fahad Specialist Hospital. Because those reasons, I’m
Interviewer him.
Formal Interview section,

8. Alfrdan: I’m Ali Alfrdan. I’m studying at Valparaiso
University, and my major is Electrical Engineering and Pre
Med. I’m in my freshman year. I’m in the process of writing my
second formal paper of my core class. It’s about worker profile
wish we have interview of someone I like his job or his
vocation. I’m very interesting of your job and vocation, so I’d
like to follow your step to be successes nephrology consultant
doctor and successes track & field player as you, so my
assignment and my curiosity drive me to interview you.
Exam #1 (covers chapters 1-5), Math 140
Spring 2015, CSUN
Show All Work!
Name:___________________________
Seat Number:_____________________
Papers without name/seat number would lose 10 points. Write
your name and seat number now.
You must show all work for full credit.
1) Define the following term: Stratified Random Sample. (6
points)
2) The amount of cash (rounded to whole dollars) carried by
each student in a simple random sample of CSUN’s
students who take MWF classes are given below: 3, 5, 8, 11, 4,

9. 11, 9, 6, 9, 21, 24, 32, 23, 18, 25, 17, 2, 1, 30,
15, 27, 28, 32, 16, 20, 8, 5, 2, 20, 15.
A) Construct a relative frequency distribution table, with the
first class having a lower class limit of 1 and a
class width of 6. (8 points)
B) Construct a relative cumulative frequency distribution
related to part (A). (4 points)
C) Construct a histogram and a pie chart for the data set in part
A, use relative frequency for both graphs. (8
points)
2
3) The average distance of students living away from campus is
10 miles. If the standard deviation is 2.5 miles,
what are the z-scores for two students who live 14 and 20 miles
away from campus? Are these z-scores usual
or unusual? Explain why or why not. (8 points)

10. 4) The following frequency distribution shows the ages of the
employees working in a movie production company
in Hollywood. Treating these data as a sample of employees in
movie industry, A) compute the mean, and
standard deviation. Comment on age distribution of the
employees. Explain. (12 points)
Age Frequency
20 - 24 11
25 - 29 19
30 - 34 25
35 - 39 20
40 - 44 10
3
5) Find the 5-number summary for the data: 2, 8, 5, 10, 15, 9,
21, 32, 17, 18, 24, 43, 28, 20. Indicate any outliers
by calculating upper and lower fences and mark all these
information on a boxplot. (16 points)

12. 4
6) Let X be the number children with green eyes in a family of
four children whose one of their parents has green
eyes. Is the following a probability distribution? If yes, then
find its mean and standard deviation. If not,
explain why not. (13 points)
X P(X)
0 0.35
1 0.25
2 0.20
3 0.15
4 0.05

13. 7) A family has three children, find the probability of having at
least two boys. Write the sample space, first. (10
points)

14. 5
8) A recent survey indicates that 55% of adults ages 40-49 live
alone. A) If we randomly select 10 adults from
that age group, what is the probability that at least one of them
lives alone? B) Is it unusual to randomly select
10 adults from that age group to find that at least 1 of them
lives alone? Why or why not? C) Find mean and
standard deviation when n is 10 and p = 0.55. (15 points)
€
x =
Σx
n
mean,
€
x =
Σf ⋅ x
Σf
mean (freq. table),
€
s =
Σ(x − x )2

15. n −1
standard deviation,
€
s =
n(Σx2)−(Σx)2
n(n −1)
standard deviation (shortcut),
€
s =
n(Σf ⋅ x2)−(Σf ⋅ x)2
n(n −1)
standard deviation (freq table), variance =
€
s2,
€
z =
x − x
s
Standard score (sample),
€

16. z =
x − µ
σ
Standard score (population),
€
IQR = Q3 −Q1,
€
LF = Q1 −1.5* IQR
lower fence ,
€
UF = Q3 +1.5* IQR upper fence,
€
µ = ΣxP(x) Mean (prob. dist.),
€
σ = Σx2P(x)− µ2 Standard
deviation (prob. dist.),
€
P(x) = (nCx)pxqn−x =
n!
x!(n − x)!

17. pxqn−x binomial probability,
€
µ = np Mean (binomial),
€
σ = npq Standard deviation (binomial)