Homework 14 B
Name_
Class Number _
1. The time to failure of 10 batteries was measured. The average time to failure of the 10 batteries is 8.65
hours. The population standard deviation is assumed to be 1.25 hours.
a) Determine a 95% confidence interval fo
HW1:
Name _
Class Number _
1. There are for local hospitals in a city. The graph below shows the number of heart patients treated at each
hospital.
Cha r t of He a r t Pa t i e nt s
140
a) What percent went to Hospital D?
127
120
127/257 = .49416 (49.42%)
The Office Hours for each TA are given below.
Rec.
A1
A2
A3
A4
A5
A6
A7
A8
B1
Time
M 10:00
M 11:00
W 9:00
W 8:00
W 12:00
W 1:00
F 10:00
F 11:00
T 5:30
TA
Yingdong Feng
Yingdong Feng
Yuxin Ding
Yuxin Ding
Xin Yang
Xin Yang
Yang Zhao
Yang Zhao
Chi Chen
TA O
Dr. Dietrich W. Kuhlmann
kuhlmann@buffalo.edu
Kimball Tower 809
Syllabus Sta119
Probability and Statistics
Spring 2016
COURSE DESCRIPTION
This course covers topics in descriptive statistics, probability, inference, and experimental design, all of
which ar
Name_
Turn in HW 5
Class Number_
1. The time to failure of 18 batteries was measured. The average time to failure of the 18 batteries is 22.81 hours
and the standard deviation of the 18 batteries is 1.55 hours. The population is assumed to be normally dis
Turn in HW 2
Name _
Class Number _
1. Data is collected on several individuals from a large university that attended a clinic. Their person type and
injury type are noted and tabulated below.
Injury
Type
Total
Person
Minor
Severe Minor Severe
Type
Fractur
Name_
Turn in HW 7
1. Use the given data to calculate
Class Number_
sp .
Company A n 16 x 63,500 s 221
Company B n 5 x 49,500 s 403
Answer
2. We wish to determine if a certain diet is effective in helping weight loss. A random sample of 10 people is
chose
Turn in HW 3
Name _
Class Number _
1. Suppose that we have a normally distributed process such that 40 and .4 .
Within 1
Within 2
Within 3
Within 4
.68269
.95450
.99730
.99993666
A Lot of the Population
Most of the Population
All but about 6 out of 100,00
Turn in HW 4
Name _
Class Number _
1. The tread life a certain brand of tires is known to be normally distributed with a mean of 50,000 miles and a
standard deviation of 4,000 miles.
a) What is the probability that a randomly selected tire will last longe
Homework 22
Name_
Class Number_
1. Data is collected to determine if men and women differ on a certain issue. Of 1500 women polled 435 said
yes to the issue. Of 900 men polled 330 said yes.
a) Do men and women differ at the .05 level?
Ho : pM pF
vs. Ha :
Using Probability in Decision Making
A friend has offered us to wager on tossing a coin. If he tosses a Heads we pay him $1. If he tosses a Tails he
pays us $1. If the coin is not a trick coin, then the probability of Tails is p .5 , the game is fair, and
Stat 119
Quiz 2
Class Number _
Name_
1. Use the CDF of X to answer the probability questions. Use CDF notation.
x
F(x)
1
.08
2
.12
3
.27
4
.28
5
.36
6
.56
7
.68
6
.15
.9
8
.83
7
.05
.35
a) P ( X = 7)
F (7) F (6) = .68 .56 = .12
b) P (5 X )
1 F (4) = 1 .28
HW2B:
Name _
Class Number _
1. A survey asked 1200 voters who they would vote for in the next election. Of those surveyed, 432 said that
they would vote for Candidate A. Determine the proportion that will vote for Candidate A.
432/1200 = .3600
2. Of the 4
HW24
1. In the general population the racial makeup of five groups is
A company employs 2000 workers. The racial makeup of the four groups in this company is:
Group
Number
1
750
2
380
3
390
4
170
5
310
Perform a .05 level test to determine if the racial m
HW4A:
Name _
Class Number _
As in the class notes, a survey is conducted and tabulated below.
Salary
Total
Degree
Under 20 20 - 30 30 - 40 Over 40
HS Degree
300
250
100
50
700
College Degree
100
250
200
200
750
Advanced Degree
0
50
250
300
600
Total
400
5
1
HW12B:
Name _
1. Determine the following:
a) P( 1.36 Z < .28)
b) P(1.19 < Z )
c) P( .36 Z 2.18)
d) P ( Z < .83)
e) P(.68 Z < .78)
f) P( 1.65 < Z )
g) Find the number k so that P( Z < k ) = .05
h) Determine
z.015
Class Number _
2
HW13A:
Name _
Class Numb
Homework 18 A
Name_
Class Number_
1. The average flight time using a certain flight path between two cities is 5.25 hours. A new flight path
between these two cities is being considered. It is hoped that this new path will reduce flight time. A sample of
HW4C:
Name _
Class Number _
1. Data is gathered from a university graduate program. Data is collected from each person applying to the
program. Of the 400 male applicants, 100 were accepted. Of the 400 female applicants 60 were accepted.
Male
Female
Total
Homework 23 A
Name_
Class Number_
1. Use the data below to test if the population standard deviations differ at the .05 level.
4.18 5.66 5.42 4.40 4.40 5.75 5.04 5.81 3.90 4.86
5.26 5.66 4.80 5.16 6.17 2.94 4.61 5.41 4.69 5.79
2. Company A claims that the
HW3A:
Name _
Class Number _
As in the class notes, a survey is conducted and tabulated below.
Salary
Total
Degree
Under 20 20 - 30 30 - 40 Over 40
HS Degree
200
250
100
50
600
College Degree
100
250
300
150
800
Advanced Degree
0
50
250
300
600
Total
300
5
Homework 15 A
Name_
Class Number _
1. The time to failure of 10 batteries was measured. The average time to failure of the 10 batteries is 8.65 hours
and the standard deviation of the 10 batteries is 1.25 hours.
a) Determine a 95% confidence interval for