I need help figuring out what tests to use for SPSS. I think I did everything ri
ID: 3054658 • Letter: I
Question
I need help figuring out what tests to use for SPSS. I think I did everything right, but I'm having a hard time determining if i should use a T Test, a 1 Way Anova, etc.
Control
131
115
124
131
122
117
88
114
150
169
SCI
60
150
130
180
163
130
121
119
130
148
The purpose of a study by Tam et al was to investigate wheelchair maneuvering in individuals with lower spinal cord injury (SCI) and healthy controls (Control). Subjects used a modified wheelchair to incorporate a rigid seat surface to facilitate the specified experimental measurements. Interface pressure measurement was recorded by using a high-resolution pressure-sensitive mat with a spatial resolution of four sensors per square centimeter taped on the rigid seat support. During static sitting conditions, average pressures were recorded under the ischial tuberosities (bottom part of the pelvic bones). The data for measurements of the left ischial tuberosity (in mm Hg) for the SCI and control groups are shown in the Table. We wish to know if we may conclude, on the basis of these data, that, in general, healthy subjects exhibit lower pressure than SCI subjects.
Scientific/Research Hypothesis:
Purpose: The purpose of the study conducted by Tam et al was to investigate wheelchair maneuvering in individuals with lower spinal cord injury (SCI) and healthy controls (control).
Research Hypothesis: The researchers hypothesize that healthy subjects will exhibit a lower mean pressure under the ischial tuberosities than subjects with a lower spinal cord injury.
Statistical/Test Hypothesis:
Null Hypothesis
H0: Mean Pressure of Healthy Controls = Mean Pressure of Spinal Cord Injury Subjects
Alternative Hypotheses
H1: Mean Pressure of Healthy Controls Mean Pressure of Spinal Cord Injury Subjects
H2:Mean Pressure of Healthy Controls > Mean Pressure of Spinal Cord Injury Subjects
Test Data & Assumptions:
The data consists of two groups of subjects (10 with a spinal cord injury and 10 without) that were observed using a modified wheelchair to determine the average pressure of the left ischial tuberosity in mm Hg. Since the dependent variable depends on the independent variable, the average pressure of left ischial tuberosity was deemed the dependent variable because it was dependent on the health of the subject (the independent variable).
Non – Parametric or Parametric: Parametric (20 Subjects – 10 with a spinal cord injury, 10 without)
Variables: 2
Dependent Variables: Mean Pressure of the Left Ischial tuberosity (mm Hg)
Independent Variables: Health of the Subject (Health of subject is in reference to whether or not they have a spinal cord injury)
Two Different Levels: With Spinal Cord Injury, No Spinal Cord Injury
Data Collection: Samples were independently (randomly) obtained
Test Statistic & Decision Rule:
Tests Used: An independent samples and T - Test were used because I was trying to find evidence of a significant difference between two population means. The greater the T Value number is, the more likely it is that there is no significant difference. However, the closer the T Value is to 0, the more likely there isn’t a significant difference.
Calculations:
Statistical Decision:
Null Hypothesis
H0: Mean Pressure of Healthy Controls = Mean Pressure of Spinal Cord Injury Subjects; reject null hypothesis
Alternative Hypotheses
H1: Mean Pressure of Healthy Controls Mean Pressure of Spinal Cord Injury Subjects; cannot reject
H2:Mean Pressure of Healthy Controls > Mean Pressure of Spinal Cord Injury Subjects; cannot reject
Statistical Conclusion:
Question: Can we conclude, that on the basis of this data that, in general healthy subjects exhibit lower pressure than SCI subjects?
Yes, we can conclude, based on this data that general healthy subjects exhibit lower pressure than subjects with a spinal cord injury since the mean pressure underneath the left ischial tuberosity for healthy subjects was 126.1 +- 21.8 mmHG and the mean pressure underneath the left ischial tuberosity for individuals with a spinal cord injury was 133.1 +- 32.2 mmHG. Although, the difference in pressure reading, between the control group and the group of individuals with a spinal cord injury, is small.
Question 2
Young
Middle-aged
Elderly
193.6
125.4
59
137.5
126.5
87.2
122
115.9
84.4
145.4
98.8
78.1
117
94.3
51.9
105.4
99.9
57.1
99.9
83.3
54.7
74
72.8
78.6
74.4
83.5
53.7
112.8
96
In a study by Wang and colleagues, researchers examined bone strength. They collected 10 cadaveric femurs from subjects in three age groups: young (19-49 years), middle-aged (50-69 years), and elderly (70 years and above). [Note: one value was missing in the middle-aged group]. One of the outcome measures was the force in Newtons required to fracture the bone. The following Table shows the data for the three groups. Analyze the data to determine if bone strength is different among the age groups.
Scientific/Research Hypothesis
Purpose: The purpose of this experiment was to examine bone strength by measuring the force required to fracture a bone.
Research Hypothesis: The researchers hypothesize that bone strength depends on the age group.
Statistical/Test Hypothesis
Null Hypothesis
H0: Mean Strength of Young Bones = Mean Strength of Middle Aged Bones = Mean Strength of Elderly Bones
Alternative Hypothesis
HA: Mean Strength of Young Bones Mean Strength of Middle Aged Bones Mean Strength of Elderly Bones
Test Data & Assumptions
Non-Parametric or Parametric: Parametric (We can assume that the 3 populations or levels are normally distributed and have equal variances)
Variables: 3
Dependent Variables: Strength of Bones (Measured by the force required to Fracture Bones in Newtons)
Independent Variables: Age Groups
Three Different Levels: Young (19-49 years), Middle-Aged (50-69 years) and Elderly (70 and above)
Data Collection: Samples were independently (randomly) obtained
Test Statistic & Decision Rule:
Tests Used: One – Way Anova
Calculation:
Statistical Decision:
Null Hypothesis
H0: Mean Strength of Young Bones = Mean Strength of Middle Aged Bones = Mean Strength of Elderly Bones; reject
Alternative Hypothesis
HA: Mean Strength of Young Bones Mean Strength of Middle Aged Bones Mean Strength of Elderly Bones; cannot reject
Statistical Conclusion:
Question: Is bone strength different among the age groups?
Since we rejected the null hypothesis, we can conclude that bone strength is different among the age groups.
Question 3
Gold et al investigated the effectiveness on smoking cessation of a nicotine patch (NP), bupropion (BP), or both nicotine patch and bupropion (NP+BP). Consecutive consenting patients (n=164) assigned themselves to one of three treatments according to personal preference, resulting in the following sample size distributions: NP (n=13); BP (n=92), NP+BP (n=59). At their first smoking cessation class, patients estimated the number of packs of cigarettes they smoked per day and the number of years they smoked. The "pack years" is the average number of packs the subject smoked per day multiplied by the number of years the subject had smoked. The results of Pack Years are shown in the Table below for the 164 study participants. The researchers are curious about whether there might be differences in pack years among the treatment groups. Please analyze the data and provide an answer to satisfy the researchers' curiosity.
Pack Years
NP
BP
NP+BP
15
8
60
90
8
80
17
10
60
90
15
80
18
15
60
90
25
82
20
20
60
95
25
86
20
22
60
96
25
87
20
24
60
98
26
90
30
25
60
98
30
90
37
26
66
99
34
90
43
27
66
100
35
90
48
29
67
100
36
90
60
30
68
100
40
95
100
30
68
100
45
99
100
35
70
100
45
100
35
70
100
45
102
39
70
105
45
105
40
75
110
48
105
40
75
110
48
105
40
75
120
49
111
40
75
120
52
113
40
76
123
60
120
40
80
125
60
120
45
80
125
60
125
45
80
126
64
125
45
80
130
64
129
50
80
130
70
130
51
80
132
70
133
52
80
132
70
135
55
84
142
75
140
58
84
157
75
154
60
84
180
76
60
90
Scientific/Research Hypothesis:
Purpose: The purpose of this experiment was to investigate the effectiveness on smoking cessation of a nicotine patch (NP), bupropion (BP), or both nicotine patch and bupropion (NP+BP).
Hypothesis: The researchers hypothesize that there is a difference in pack years among treatment groups.
Statistical/Test Hypothesis:
Null Hypothesis
H0: Mean of Pack Years = Mean of Nicotine Patch = Mean of Bupropion = Mean of Nicotine Patch and Bupropion
Alternative Hypothesis
HA: Mean of Pack Years Mean of Nicotine Patch Mean of Bupropion Mean of Nicotine Patch and Bupropion
Test Data & Assumptions:
The result of the treatment option depends on the pack years.
Non-Parametric or Parametric: Parametric
Variables: 3
Dependent Variables: Pack Years
Independent Variables: Treatment Group
Three Levels: nicotine patch (NP), bupropion (BP), or both nicotine patch and bupropion (NP+BP)
Data Collection:
Test Statistic & Decision Rule:
Tests Used: Tukeys HSD, 1 Way Anova
a. Determine the appropriate test statistic to be used (considering the test data properties).
Parametric or nonparametric?
- Samples from normally distributed population?
- Samples independently (randomly) obtained (this applies to all tests)
- Similar variances among the populations? (Homoscedasticity)
- Variable measured on interval or ratio scale? (Values manipulable by conventional arithmetic?)
b. Decide whether this is a one-tailed or two-tailed test.
c. Define a critical value for the test statistic, ie, the cutoff point beyond which the null hypothesis would be rejected and the alternative hypothesis may be accepted (or cannot be rejected).
Consider the risks of Type I error (erroneously rejecting null hypothesis)
or Type II error (erroneously rejecting the alternative hypothesis).
d. Anticipate whether the test has adequate power (sufficiently high probability that the null
hypothesis is correctly rejected).
Given that normality of uCA distribution can be assumed, there are two before-and-after groups to be compared, a paired samples t-test is selected for the data, and will be evaluated at an alpha value=0.05.
H1 pertains to alterations up or down, hence a two-tailed test will be applied.
H2 pertains to mean uCa (control) being smaller than uCa (vitD3), hence a one-tailed test will be applied.
Calculation:
Statistical Decision:
Statistical Conclusion:
Question: Is there a difference in pack years among the treatment groups?
Question 4
Anxiety patients admitted to a clinic were placed on a stress reduction study to assess the effectiveness of the program. Among the data collected were the patient scores on the Hamilton Anxiety Rating Scale at three different points in time: pretreatment, post-treatment, and three-month follow-up. Assuming that the Hamilton Scale is a continuous distribution with values between 0 and 56 within the studied population, was the stress reduction program effective in reducing the patients' stress scores?
HARS Scores
Subject
Initial
Pre
Post
3month
1
21
21
16
19
2
30
38
10
21
3
38
19
15
6
4
43
33
30
24
5
35
34
25
10
6
40
40
31
30
7
27
15
11
6
8
18
11
4
7
9
31
42
23
27
10
21
23
21
17
11
18
24
16
13
12
28
8
5
2
13
40
37
31
19
14
35
32
12
21
Scientific/Research Hypothesis
Purpose: The purpose of this experiment was to assess the effectiveness of a stress reduction program on patients who had anxiety.
Hypothesis: The researchers hypothesize that the stress reduction program was effective in reducing the patients’ stress scores.
Statistical/Test Hypothesis
H0 (Null Hypothesis): Mean of Pre Treatment = Mean of Post Treatment = Mean of Follow-up
HA (Alternative Hypothesis): Mean of Pre Treatment Mean of Post Treatment Mean of Follow-up
Test Data & Assumptions
Non-Parametric or Parametric: Parametric
Dependent Variables: HARS Score
Independent Variables: Period of Time
Four Different Levels: Initial, Pre, Post, and 3 Month Follow Up
Data Collection: Repeated Samples
Test Statistic & Decision Rule:
Tests Used: One – Way Anova with Repeated Measures
Calculation:
Statistical Decision:
H0 (Null Hypothesis): Mean of Pre Treatment = Mean of Post Treatment = Mean of Follow-up; cannot reject
HA (Alternative Hypothesis): Mean of Pre Treatment Mean of Post Treatment Mean of Follow-up; cannot reject
Statistical Conclusion:
Question 5
In a study of pulmonary effects on guinea pigs, Lacroix et al exposed 18 ovalbumin-sensitized guinea pigs and 18 nonsensitized guinea pigs to regular air, benzaldehyde, and acetaldehyde. At the end of exposure the guinea pigs were anesthetized and allergic responses were assessed in bronchoalveolar lavage (BAL). The following table shows the alveolar cell count (x106) by treatment group for the ovalbumin-sensitized and nonsensitized guinea pigs. Test for differences (a) between ovalbumin-sensitized and nonsensitized outcomes, (b) among the three different exposures, and [c] interaction.
Ovalbumin-sensitized?
Treatment
Alveolar count (x106)
No
Acetaldehyde
49.9
No
Acetaldehyde
50.6
No
Acetaldehyde
50.35
No
Acetaldehyde
44.1
No
Acetaldehyde
36.3
No
Acetaldehyde
39.15
No
Air
24.15
No
Air
24.6
No
Air
22.55
No
Air
25.1
No
Air
22.65
No
Air
26.85
No
Benzaldehyde
31.1
No
Benzaldehyde
18.3
No
Benzaldehyde
19.35
No
Benzaldehyde
15.4
No
Benzaldehyde
27.1
No
Benzaldehyde
21.9
Yes
Acetaldehyde
90.3
Yes
Acetaldehyde
72.95
Yes
Acetaldehyde
138.6
Yes
Acetaldehyde
80.05
Yes
Acetaldehyde
69.25
Yes
Acetaldehyde
31.7
Yes
Air
40.2
Yes
Air
63.2
Yes
Air
59.1
Yes
Air
79.6
Yes
Air
102.45
Yes
Air
64.6
Yes
Benzaldehyde
22.15
Yes
Benzaldehyde
22.75
Yes
Benzaldehyde
22.15
Yes
Benzaldehyde
37.85
Yes
Benzaldehyde
19.35
Yes
Benzaldehyde
66.7
Scientific/Research Hypothesis
Purpose: The purpose of this experiment was to study the pulmonary affects different treatments have on guinea pigs.
Hypothesis: The researchers hypothesize that there is a difference that occurs between ovalbumin-sensitized and nonsensitized outcomes, among the three different exposures, and interaction.
Statistical/Test Hypothesis
Ovalbumin Sensitized & Non-Sensitized Guinea Pigs
H0 (Null Hypothesis): Mean of Ovalbumin Sensitized = Mean of Non- sensitized guinea pigs
HA (Alternative Hypothesis): At least two of the means differ
Three Different Exposures
H0 (Null Hypothesis): Mean of Benzaldehyde = Mean of Air = Mean of Acetaldehyde
HA (Alternative Hypothesis): At least two of the means differ
Interaction
H0 (Null Hypothesis): Interaction does not exist.
HA (Alternative Hypothesis): Interaction does exist.
Test Data & Assumptions
There were two groups of guinea pigs, one that had
Non-Parametric or Parametric
Dependent Variables: Aveolar Count
Independent Variables: Treatment and Ovalbumin Sensitivity
Three Levels of Treatment: Regular Air, Benzaldehyde, and Acetaldehyde
Data Collection
Test Statistic & Decision Rule:
Tests Used: Two – Way Anova / Univariate Analysis of Variance with Descriptive Power
Post Hoc Test: Tukey HSD, Duncan
Calculation:
Statistical Decision:
Ovalbumin Sensitized & Non-Sensitized Guinea Pigs
H0 (Null Hypothesis):Mean of Ovalbumin Sensitized = Mean of Non- sensitized guinea pigs; cannot reject
HA (Alternative Hypothesis): At least two of the means differ; cannot reject
Three Different Exposures
H0 (Null Hypothesis):Mean of Benzaldehyde = Mean of Air = Mean of Acetaldehyde; cannot reject
HA (Alternative Hypothesis): At least two of the means differ; cannot reject
Interaction
H0 (Null Hypothesis):Interaction does not exist.
HA (Alternative Hypothesis): Interaction does exist. ; cannot reject
Statistical Conclusion:
Control
131
115
124
131
122
117
88
114
150
169
SCI
60
150
130
180
163
130
121
119
130
148
Explanation / Answer
1) I need help figuring out what tests to use for SPSS. I think I did everything right, but I'm having a hard time determining if i should use a T Test, a 1 Way Anova, etc.
Purpose: The purpose of the study conducted by Tam et al was to investigate wheelchair maneuvering in individuals with lower spinal cord injury (SCI) and healthy controls (control).
Research Hypothesis: The researchers hypothesize that healthy subjects will exhibit a lower mean pressure under the ischial tuberosities than subjects with a lower spinal cord injury.
Two sample t-test.
2) Scientific/Research Hypothesis
Purpose: The purpose of this experiment was to examine bone strength by measuring the force required to fracture a bone.
Research Hypothesis: The researchers hypothesize that bone strength depends on the age group.
Here we use one way anova because we test three means.
Q.3)
Scientific/Research Hypothesis
Purpose: The purpose of this experiment was to examine bone strength by measuring the force required to fracture a bone.
Research Hypothesis: The researchers hypothesize that bone strength depends on the age group.
Here also we used one way anova with post hoc.
Q4)
Scientific/Research Hypothesis
Purpose: The purpose of this experiment was to assess the effectiveness of a stress reduction program on patients who had anxiety.
Hypothesis: The researchers hypothesize that the stress reduction program was effective in reducing the patients’ stress scores.
Here pre and post observations taken therefore we use one way anova with repeated measure.
Q.5) Scientific/Research Hypothesis
Purpose: The purpose of this experiment was to study the pulmonary affects different treatments have on guinea pigs.
Hypothesis: The researchers hypothesize that there is a difference that occurs between ovalbumin-sensitized and nonsensitized outcomes, among the three different exposures, and interaction.
Here we use two way anova.
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