Use the following problems for your hypothesis test portfolio. Put the type of test at the center top
and then glue the problem at the top of the page and then perform the hypothesis test, draw a line and
do the interval at the bottom of the page. You do not need to restate the parameter and assumptions
for the intervals. Show all necessary steps. Only put one problem per page and at the end you will
arrange these by putting the one sample tests first (means then proportions) and then the two sample
tests (means then proportions) and then the chi-square and linear regression tests.
1.
In a recent year, 73% of first year college students responding to a national survey identified
“being very well-off financially” as an important personal goal. A state university finds that 132
of an SRS of 200 of its first-year students say that this goal is important. Is there good
evidence that the proportion of first-year students at this university who think being very welloff is important differs from the national value. Use  = 0.01.
2. An agronomist examines the cellulose content of a variety of alfalfa hay. Suppose that the
cellulose content in the population has standard deviation of 8 mg/g. A sample of 35 cuttings
has a mean cellulose content of 145 mg/g. A previous study claimed that the mean cellulose
content was 140 mg/g, but the agronomist believes that the mean is higher than that figure.
Carry out a significance test to see if the new data support this belief.
3. A study of the relationship between men’s marital status and the level of their jobs used data on
all 8235 male managers and professional employed by a large manufacturing firm. Each man’s job
has a grade set by the company that reflects the value of that particular job to the company.
The authors of the study grouped the many job grades into quarters. Grade 1 contains jobs in
the lowest quarter of job grades and grade 4 contains those in the highest quarter. Do these
data show a statistically significant relationship between marital status and job grade?
Job
Grade
1
2
3
4
Single
58
222
50
7
Married
874
3927
2396
533
Divorced Widowed
15
8
70
20
34
10
7
5
4. The dean of students wants to see whether there is a significant difference in ages of resident
students and commuting students.
Resident
Commuter
22
18
25
20
27
19
23
25
26
36
24
30
25
25
20
24
26
22
27
19
18
27
5. In a survey of gun control laws, a random sample of 40 women showed that 26 were in favor of
stricter gun control laws. A random sample of 60 men showed that 37 were in favor of stricter
gun control laws. Is the proportion of women who favor gun control laws greater than the
proportion of men. Test using a 1% significance level.
6. The design of controls and instruments affects how easily people can use them. A student
project investigated this effect by asking 25 right-handed students to turn a knob (with their
right hands) that moved an indicator by screw action. There were two identical instruments, one
with a right-hand thread (knob turns clockwise) and the other with a left-hand thread (knob
turns counterclockwise). The following table give the times in seconds each subject took to move
the indicator a fixed distance. The project hoped to show that right-handed people find righthand threads easier to use. Carry out a test of your hypothesis.
Subject
1
2
3
4
5
6
7
8
9
10
11
12
13
Right thread
113
105
130
101
138
118
87
116
75
96
122
103
116
Left thread
137
105
133
108
115
170
103
145
78
107
84
148
147
Subject
14
15
16
17
18
19
20
21
22
23
24
25
Right thread
107
118
103
111
104
111
89
78
100
89
85
88
Left thread
87
166
146
123
135
112
93
76
116
78
101
123
. 7. The chair of the history department of a college hypothesizes that the final grades are distributed as 35% A's, 25%
B's, 20% C's, 15% D's and 5% F's. At the end of the semester, the following numbers of grades were earned. For 
= 0.05, is the grade distribution for the department different from that expected?
Grade
Number
A
45
B
52
C
39
D
8
F
6