Identifying Risks and Hazards - Part 1, PUBH 6033 Assignment Solution

This document provides a complete solution to a Week 10 assignment for PUBH 6033, focusing on identifying risks and hazards associated with asbestos exposure and lung cancer. The assignment requires students to analyze a dataset using SPSS, performing a chi-square test for independence and calculating the odds ratio. The solution includes setting up null and alternative hypotheses, determining the level of significance, selecting the appropriate test statistic, establishing a decision rule, and computing the chi-square value using SPSS. The SPSS output, including cross-tabulation tables and risk estimates, is provided. The conclusion of the analysis confirms a statistically significant association between asbestos exposure and lung cancer, leading to the rejection of the null hypothesis. The document offers a step-by-step guide to statistical analysis and interpretation within a public health context.

Running head: IDENTIFYING RISKS AND HAZARDS – PART 1
Identifying Risks and Hazards – Part 1
Name
Course Number
Date
Faculty Name

IDENTIFYING RISKS AND HAZARDS 2
PUBH 6033—Week 10 Assignment 1
Identifying Risks and Hazards—Part 1
(Rubric included)
Instructions
For this Assignment, review this week’s Learning Resources. Open SPSS and then use the
file/open/data command to open the dataset asbestos.sav. This is data collected on the
incidence of lung cancer for those exposed to asbestos and those not exposed.
Run a chi-square for independence and odds ratio analysis as per this Week’s demonstration
video. Then, provide your response to all items in this worksheet.
Note: You will use the SPSS Output generated in this Assignment 1 to complete Assignment 2 as
well.
Submit this Application Assignment by Day 7.
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Note: Scores are to be entered by instructor
Step 1: Set up your hypothesis and determine the level of significance
1. State the alternative/research hypothesis in written format.
Answer: HA: There is a statistically significant association between exposure to asbestos and
lung cancer ____ / 6 points
2. State the null hypothesis in written format
Answer: The association between exposure to asbestos and lung cancer is not statistically
significant at the predetermined confidence level. Eg 95%. ____ / 6 points
3. What is your level of significance (choose α = .05 or α = .01)?
Answer: The level of significance for the test is 0.05 (5%). This level represents the chance of
failing to accept the null hypothesis when the alternative is not true. Most statistical tests use
5% percent to improve the probability of detecting a significant difference when comparing the
resulting p-value with 0.05. ____ / 4 points
Step 2: Select the appropriate test statistic
4. What is the appropriate test statistic?
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IDENTIFYING RISKS AND HAZARDS 3
Answer: The appropriate test statistic is the chi-square test of association compared between
calculated and tabulated values. This is because the test is aimed at determining whether there
is a difference the exposed and non-exposed groups on the ratio of lung cancer. The statistic is
calculated using observed and expected value of a contingency table with rows as asbestos
exposure and columns as lung cancer. ____ / 4 points
Step 3: Set up the decision rule
5. Based on the level of significance you set in step 1 and test statistic in step 4, what
is your decision rule?
Note: Because there are 2 rows and 2 columns, the total degrees of freedom is 1.
Answer: If the calculated chi-square statistic is greater than the tabulated value at α=0.05 and 1
degree of freedom (ꭓ2 (0.05, 1) = 3.841), we reject the null hypothesis. ____ / 6 points
Step 4: Compute the test statistic Open SPSS and then use the file/open/data command to open the dataset asbestos.sav.
 Select: Analyze > Descriptive Statistics > Crosstabs
 Move asbestos to the Row(s) box, and lungca to the Column(s) box. Click on Statistics and
make sure Chi-Square and RISK are checked. Click on Cells, and check Observed and
Expected (frequencies). Click Continue; click OK.
6. What is the χ2 value computed by your SPSS analysis?
Answer: The calculated chi-square value is 121.154. ____ / 4 points
7. Paste your SPSS output here:
Answer:
Table 1: Cross tabulation of Exposure to asbestos and lung cancer
Lung Cancer Total
Yes No
Exposed to Asbestos Yes Count 97 33 130
Expected Count 52.0 78.0 130.0
No Count 15 135 150
Expected Count 60.0 90.0 150.0
Total Count 112 168 280
Expected Count 112.0 168.0 280.0
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IDENTIFYING RISKS AND HAZARDS 4
Table 2: SPSS Output table of Chi-square tests
Value Degrees
of
Freedo
m
Asymptotic
Significanc
e (2-sided)
Exact Sig.
(2-sided)
Exact Sig. (1-
sided)
Pearson Chi-
Square
121.154
a
1 .000
Continuity
Correctionb
118.476 1 .000
Likelihood Ratio 132.066 1 .000
Fisher's Exact Test .000 .000
N of Valid Cases 280
a. 0 cells (0.0%) have expected count less than 5. The minimum expected count is 52.00.
b. Computed only for a 2x2 table
Table 3: A table of risk estimates
Value 95% Confidence Interval
Lower Upper
Odds Ratio for Exposed to Asbestos
(Yes / No)
26.455 13.622 51.376
For cohort Lung Cancer = Yes 7.462 4.569 12.185
For cohort Lung Cancer = No .282 .209 .381
N of Valid Cases 280
____ / 20 points
Step 5: Conclusion
8. Do you reject or fail to reject the null hypothesis?
Answer: The calculated chi-square statistic is greater than the tabulated value (3.841), hence
rejecting the null hypothesis is. ___ / 6 points
9. Is there an association between asbestos exposure and lung cancer?
Answer: Based on the calculated chi-square statistic and the p-value, we conclude that there is
a significant association between asbestos exposure and lung cancer at 95% confidence level.
____ / 4 points
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IDENTIFYING RISKS AND HAZARDS 5
Section below (scoring) is to be completed by Instructor
Scoring Rubric for Week 10 Assignment1
Identifying Risks and Hazards—part 1 (60 points)
Initial Score (60 possible points):
Timeliness Factor (late points deducted):
Total Score (60 possible points):
Instructor comments:
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