How big are tomatoes? Some say that depends on the growing conditions. A random sample of n1 =89 organically grown tomatoes had a sample mean weight of ounces. Another random sample of n2 = 75 tomatoes that were not organically grown had a sample mean weight of ounces.

Set up Ho, Ha, and tell which test and why. Do not complete the test. (10 points)
How big are tomatoes? Some say that depends on the growing conditions. A random sample of n1 =89 organically grown tomatoes had a sample mean weight of ounces. Another random sample of n2 = 75 tomatoes that were not organically grown had a sample mean weight of ounces. Previous studies show that ounce and ounces. Does this indicate a difference either way between population mean weights of organically grown tomatoes compared to those that are not organically grown?
2. Set up Ho, Ha, and tell which test and why. Do not complete the test. (10 points)
How old are college students? The national distribution for college students is shown below.

Age
Under 26
26-35
36-45
46-55
Over 55
Number of students
39%
25%
16%
12%
8%

The Western Association of Mountain Colleges took a random sample of 212 students and obtained the following sampling distribution.

Age
Under 26
26-35
36-45
46-55
Over 55
Number of students
65
73
41
21
12

Is the sample age distribution for the Western Association of Mountain Colleges a good fit to the national distribution?

3. Complete the hypothesis test
A system specialist has studied work-flow of clerks all doing the same inventory work. Based on this study, she designed a new work-flow layout for the inventory system. To compare average production for the old and new methods, a random sample of 6 clerks was used. The average production rate (number of inventory items processed per shift) for each clerk was measured before and after the new system was introduced. The results are shown below. Test the claim that the new system increases the mean number of items processed per shift. Use = .05. (20 points)
Clerk
1
2
3
4
5
6
B: Old
116
108
93
88
119
111
A: New
123
114
112
82
127
119
111
122

4. Complete the hypothesis test

Are teacher evaluations independent of grades? After midterm, a random sample of 284 students was asked to evaluate teacher performance. The students were asked to supply their midterm grade in the course being evaluated. In this study, only students with passing grades (A, B, or C) were included in the summary table. Use the 5% significance level to test the claim that teacher evaluations are independent of midterm grades. (20 points)

Midterm grade

Teacher evaluation
A
B
C
Row total
Positive
35
33
28
96
Neutral
25
46
35
106
Negative
20
22
40
82
Column total
80
101
103

5. Complete the hypothesis test
This problem is based on information taken from Life in Americas Fifty States, by G. S. Thomas. A random sample of 153 people ages 16 to 19 were taken from the island of Oahu, Hawaii, and 12 were found to be high school dropouts. Another random sample of 128 people ages 16 to 19 were taken from Sweetwater, Wyoming, and 7 were found to be high school dropouts. Do these data indicate that the population proportion of high school dropouts on Oahu is different from that of Sweetwater County? (20

6. Complete the hypothesis test
High levels of cholesterol in the blood are not healthy in either humans or dogs. Because a diet rich in saturated fats raises the cholesterol level, it is plausible that dogs owned as pets have higher cholesterol levels than dogs owned by a veterinary research clinic. Normal levels of cholesterol based on the clinics dogs would be misleading. A clinic compared healthy dogs it owned with healthy pets brought to the clinic to be neutered. The summary statistics for blood cholesterol levels (milligrams per deciliter of blood) appear below. Is this good evidence that there is a difference between the clinic dogs and the dogs owned as pets? (20 points)
Group
N
Mean
Standard deviation
Pets
26
193
68
Clinic
23
174
44