For these problems, please use Excel to show your work, and submit the Excel spreadsheet along with your completed assignment. Find the point estimate of the population mean and the margin of error for a 90% confidence interval for the following drive times (in minutes) for commuters to a college. 35 40 47 22 17 19 36 44 65 55 22 23 16 46 44 38 29 22 37 16 8 15 27 41 45 17 11 45 63 17 28 19 64 55 53 50 Answer: X = S = 1231 = 34.1 Sample Mean n 36 Use the results from the above data (#1) and determine the minimum survey size that is necessary to be 95% confident that the sample mean drive time is within 10 minutes of the actual mean commuting time. In a random sample of 35 tractors, the annual cost of maintenance was $4,425 and the standard deviation was $775. Construct a 90% confidence interval for this. Assume the annual maintenance costs are normally distributed. Answer: 90% = mean ± 1.645 SEm SEm = SD/√n I used the table in the back of my statistics text labeled "areas under normal distribution" to find the proportion/probability (±5%) to get Z = 1.645. I assume that you have a similar table available. The following data represents the number of points scored by players on a high school basketball team this season. Player 1 68 Player 6 128 Player 2 82 Player 7 66 Player 3 145 Player 8 54 Player 4 111 Player 9 221 Player 5 97 Player 10 99 Find the sample mean and the sample standard deviation. Answer: Sample Mean 1071 = 107.1 Sample Standard Deviation S = 3.16 10 Construct a 90% confidence interval for the population mean and interpret the results. Assume the population of the data set is normally distributed. For the following statements, state the null and alternative hypotheses and identify which represents the claim. Determine when a type I or type II error occurs for a hypothesis test of the claim. Determine whether the hypothesis test is left-tailed, right-tailed, or two-tailed, and explain your reasoning. Explain how you should interpret a decision that rejects the null hypothesis. Explain how you would interpret a decision that fails to reject the null hypothesis. It is reported that the number of residents in Wisconsin who support plans to recall the governor is 48%. An Amish bakery store states that the average shelf life of their fresh baked goods is seven days. A soda manufacturer states that the average number of calories in the regular soda is less than 150 calories per serving. The census figures show that the average income for a family in a rural region is approximately $34,860 per year. A random sample has a mean income of $33,566 per year, with a standard deviation of $1,245. At a sig. level of .0.01 is there enough evidence to reject the claim? Explain. An advertising firm claims that the average expenditure for advertising for their customers is at least $12,500.

1. For these problems, please use Excel to show your work, and
submit the Excel spreadsheet along with your completed
assignment.
Find the point estimate of the population mean and the margin
of error for a 90% confidence interval for the following drive
times (in minutes) for commuters to a college.
35
40
47
22
17
19
36
44
65
55

2. 22
23
16
46
44
38
29
22
37
16
8
15
27
41
45
17

3. 11
45
63
17
28
19
64
55
53
50
Answer:
X
=
S
=
1231

4. = 34.1 Sample Mean
n
36
Use the results from the above data (#1) and determine the
minimum survey size that is necessary to be 95% confident that
the sample mean drive time is within 10 minutes of the actual
mean commuting time.
In a random sample of 35 tractors, the annual cost of
maintenance was $4,425 and the standard deviation was $775.
Construct a 90% confidence interval for this. Assume the annual
maintenance costs are normally distributed.
Answer:
90% = mean ± 1.645 SEm

5. SEm = SD/√n
I used the table in the back of my statistics text labeled "areas
under normal distribution" to find the proportion/probability
(±5%) to get Z = 1.645. I assume that you have a similar table
available.
The following data represents the number of points scored by
players on a high school basketball team this season.
Player 1
68
Player 6
128
Player 2

6. 82
Player 7
66
Player 3
145
Player 8
54
Player 4
111
Player 9
221
Player 5
97
Player 10
99
Find the sample mean and the sample standard deviation.
Answer:

7. Sample Mean
1071
= 107.1
Sample Standard Deviation S = 3.16
10
Construct a 90% confidence interval for the population mean
and interpret the results. Assume the population of the data set
is normally distributed.
For the following statements, state the null and alternative
hypotheses and identify which represents the claim. Determine
when a type I or type II error occurs for a hypothesis test of the
claim. Determine whether the hypothesis test is left-tailed,
right-tailed, or two-tailed, and explain your reasoning. Explain
how you should interpret a decision that rejects the null
hypothesis. Explain how you would interpret a decision that
fails to reject the null hypothesis.
It is reported that the number of residents in Wisconsin who
support plans to recall the governor is 48%.
An Amish bakery store states that the average shelf life of their

8. fresh baked goods is seven days.
A soda manufacturer states that the average number of calories
in the regular soda is less than 150 calories per serving.
The census figures show that the average income for a family in
a rural region is approximately $34,860 per year. A random
sample has a mean income of $33,566 per year, with a standard
deviation of $1,245. At a sig. level of .0.01 is there enough
evidence to reject the claim? Explain.
An advertising firm claims that the average expenditure for
advertising for their customers is at least $12,500 per year. You
want to test this claim, so you randomly select 10 of their
customers. The results are listed below. At a sig. level of .01
can you reject this claim? Explain.
13,445
11,220
10,157
13,217
9,990
12,125

9. 10,116
14,350
13,590
12,100
Find the critical value(s) for the indicated test for a population
variance, sample size, and sig. level.
Right-tailed test – Sample Size (25), Significance (.05)
Two-tailed test – Sample Size (11), Significance (.01)
Two-tailed test – Sample size (66), Significance (.10)
Left-tailed test – Sample Size (18), Significance (.05)
The employees in a grocery store are handing out samples of a
certain brand of Pizza. This is the pizza company’s way of
determining whether people like the brand of pizza and would
prefer it over other brands. Do you think this type of sampling
is representative of the population? Explain. Identify possible
flaws or biases in this study.
10.
Classify the following as independent or dependent and explain
your answer.

10. a.
Sample 1 – The males in the class
Sample 2 – The females in the class
b.
Sample 1 – Blood Pressure of fifteen people in a nursing home
c.
Sample 2 – Blood pressure of the same fifteen people one week
later
11.
A researcher claims that taking a protein supplement as part of a
weight gainer program for athletes will help them gain muscle
weight. The weights in pounds of 10 athletes are listed below
before and after using the protein supplement.
At a sig. of .05 can you conclude that this supplement helps the
athletes gain weight?
Athlete
1
2

11. 3
4
5
6
7
8
9
10
Weight Before
196
220
187

12. 184
206
198
174
176
182
174
Weight After
198
224
185
185

13. 213
196
178
180
175
174
12.
Technology:
A math teacher claims that the average final exam scores for the
seventh grade boys and girls are equal. The average score for 10
randomly selected boys is 87 with a standard deviation of 11.
The average score for 10 randomly selected girls is 89 with a
standard deviation of 12. State the null and alternate
hypotheses. At a sig. of .05 can you reject the teacher’s claim?
Assume normal distribution and equal variances. Please use
Excel for your calculations. What is your analysis?
13.

14. Application:
Create a small data set based on something you are interested
in. You will need to form a null and alternate hypothesis and
perform a one-sample test based on the sample. Discuss your
analysis based on the output. If you are unsure of ideas for a
data set, you can look online or in your text for ideas. However,
do not copy word-for-word.
Team
Offense Scored
Points Allowed
Blazers
45
38
Blue Jays
42

15. 45
Coyotes
39
38
Highlanders
48
45
Mountaineers
31
49
Rapid Falls
40

16. 45
Tronado's
39
37