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I have some exercises as I attached
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Part I:
(13 Points)
1-A researcher has collected the following sample data. Refer to the data below
calculate the independent t-test & P value finally write the conclusion. Where
S1=5.128 and S2= 3.563
(3 Point)
X1
5
11
8
12
17
X2
3
5
4
2
6
2- A snack manufacturer produces three types of chips in two different rooms (Room
1 and Room 2). Sometimes bags of chips are damaged in the packaging process. Each
bag in a random sample of 53 bags of chips packaged at Room 1 and in a random
sample of 27 bags of chips packaged at Room 2 was classified into one of three
categories: no damage, minimal damage, and severe damage. The resulting data is
summarized in the table below. The manufacturer was interested in determining if
there was sufficient evidence to conclude that the proportions falling into each of the
three damage categories is not the same for the two Rooms.
(5 Points)
Minimal
Damage
20
Severe
Damage
14
Row Totals
Room 1
No
Damage
19
Room 2
6
8
13
27
Column Totals
25
28
27
80
1
53
3- In an experiment comparing two feeding methods for calves , eight pairs of twins
were used one twin receiving method A and the other twin receiving method B. At the
end of a given time ,the Calves were slaughtered and cooked ,and the meat was rated
for its taste with a higher number indicating a better taste. Where SD=2.53 ( 5 point
)
Twin pair Method A
Method B
1
27
23
2
37
28
3
31
30
4
38
32
5
29
27
6
35
29
7
41
36
8
37
31
Part II: Multiple-Choice questions (13 point )
1. The standard deviation and the mean of 16 values are 15.6 and 20.5. The coefficient of
variation is ———-2. For a set of data we find that we have a standard deviation of 28 and a sample size of 8.
What is the standard error?
3. The hourly wages of a sample of 130 system analysts are given: What does the coefficient
of variation equal? Mean = 60 median = 74, range = 20, variance = 324
4. Suppose you have collected data from 8 subjects for each level of student. The mean for
level A was 16 and the standard deviation was 8. The mean for level B was 10 and the
standard deviation was 4. What is the t value for this test?
5. Dr Eme wrote in his results section t (15) = 15.68, p = 001. To what statistic does the 15
refer?
6. If you obtain a score of 33 on an anxiety questionnaire and you know that the population
mean and standard deviation are 15 and 8 respectively, what is your zscore?
2
7. Assume the cholesterol levels in a certain population have mean ยต= 20 and standard
deviation S = 24. The cholesterol levels for a random sample of n = 10 individuals are
measured and the sample mean x is 18.5. What is the z-score for x = 10?
8. A researcher in the field of educational psychology is interested in the effects an open
classroom has on intellectual development. In the open classroom things are much less
structured than in a traditional classroom and she believes that this might affect
problemsolving skills. An elementary school in her district switched to an open classroom
format last year, and she is interested to see how this has impacted on the kids problemsolving skills. She obtains a random sample of 49 fourth grade children and administers a
conceptual problem-solving test to them. It is known that fourth graders in traditional
classes have an average score of 82 on the test. The children in this study score an average
of 86 with a standard deviation of 5. ( 5 point)
a- Which type of statistical test should the researcher do?
b-What is the value of the standard error of the mean?
c- What is the value of the correct-test statistic?
d- Researchers decide statistical significance based on the associated with the data
set.
9. Suppose that n = 15 and that we want to test whether the population mean is equal to 16.
The sample mean is found to be 18 and the sample standard deviation is 10. Compute the pvalue for this test.
Third part : ( 14 point )
1-Dr. B make a research in 2013 “the effect of health education program for five
diabetic women before start the program check the glucose level for the women and
after finished the program check the glucose level. The result of test in the table
below ( 5 point)
A. What is your computed answer?
B. What would be the null hypothesis in this study?
3
C. What would be the alternate hypothesis?
D. Interpret your answer
Problem II:
A restaurant offers both dine-in and take-out service. Customers can pay for their meal
in cash, by credit card or by debit card. The restaurant owner wonders if thereis an
association between the method of payment and the type of service. To investigate,
a random sample is selected from the orders placed during the last year and the
method of payment and the type of service is recorded for each of these orders. The
data is summarized in the table below. (5 Points)
A. What is your computed answer?
B. Interpret your answer
Problem III:
A researcher at Basin of Lower and Upper England University (BLUE U.) is obsessed
with colours. He wants to examine whether wearing the colour blue actually leads to
better test performance. To test for group differences, the researcher randomly
assigns students to two independent groups. One is the Experimental group (Group A)
that is required to wear blue outfits to their next exam (the treatment). The other
(Group B) is the control group that wears their normal clothes to the exam. Their
scores on a 10-point test are presented below. Draw conclusions based on your
obtained t-statistic (4 points)
A. What is your computed answer?
B. What would be the null hypothesis in this study?
C. What would be the alternate hypothesis?
D. Interpret your answer
4
5
6
7
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