Week 4 Project - STAT 3001 Solution


Student Name:            <Type your name here

Date:   <Enter the date on which you began working on this assignment.

 

Instructions:  To complete this project, you will need the following materials:

 

·         STATDISK User Manual (found in the classroom in DocSharing)

·         Access to the Internet to download the STATDISK program.

 
Please complete Homework, Content Review Quiz and This Project for W4.


Part I.  Analyze Data

Instructions
Answers
1.      Open the file COTININE using menu option Datasets and then Elementary Stats, 9th Edition.  This file contains some information about a collection of movies. How many observations are there in this file?

 
In this file, there are three variables, labeled Smokers, ETS, and No ETS.  The dataset was collected for a study of second-hand smoke. The sample data consists of the measured serum cotinine levels in three different groups of people.

·         The NOETS group lists the cotinine levels for subjects who are nonsmokers and have no exposure to environmental tobacco smoke at home or work.

·         The ETS group lists cotinine levels for subjects who are nonsmokers exposed to tobacco smoke at home or work.

·         The SMOKERS group lists cotinine levels for subjects who report tobacco use. 

Serum cotinine is a metabolite of nicotine, meaning that cotinine is produced when nicotine is absorbed by the body. Higher levels of cotinine correspond to higher levels of exposure to smoke that contains nicotine.

 
2.      What results do you expect to find in this data? 


Part II. Descriptive Statistics

3.      Generate descriptive statistics for all three groups of people and complete the following table.  Round all results to 2 decimal places.
Variable
Sample

Mean
Sample

Standard Deviation
Sample Size
Smokers
 
 
ETS
 
 
No ETS
  
4.      Did you get the results you expected here?  Explain why.
 
5.      In which of the three groups did we experience the MOST variation (highest deviation from the mean)?
 
 
Part III. Confidence Intervals

6.      Generate a 95% interval for the mean of the SMOKERS group. Paste your results here.
 
7.      Generate a 95% interval for the mean of the ETS group. Paste your results here.
 
8.      Generate a 95% interval for the mean of the No ETS group. Paste your results here
 
9.      Create a graph below by illustrating all three confidence intervals on one graph using the tools in your word processor (example below).  Statdisk cannot do this for you. Creat your graph and turn the font red.  For this process, I just use the dashes and wrote a scale below the axes. 

 

    Here is an example, but it is not based on the data you are analyzing:

 

           Case 1                         14---------------------42

           Case 2                                               35-------------------------70

                                   ________________________________________

                       0                20                 40                 60
Your Solution:

  
11.       Based on the confidence intervals shown above, does there appear to be some evidence to indicate that exposure to tobacco smoke corresponds to higher levels of cotinine?

 
Part IV. Hypothesis Testing


12.   Let’s say that you are trying to show that the level of cotinine is equal to zero (0) for people who do not smoke and are not exposed to Environmental Smoke.  Compose and test a hypothesis (use Significance of 0.01) that the cotinine levels are significantly different from 0 for the No ETS group.   Show all steps.


Step 1.  Determine parameter of interest and compose null and alternative hypotheses.
 
Step 2.  Determine the sample mean, sample standard deviation, and sample size.  [Hint:  You did this in an above step in this assignment.]
 
Step 3.  Determine the likelihood that the population mean is actually equal to 0 by completing a Hypothesis Test: One Mean in STATDISK.   Use significance of 0.01.  Paste results here.
 
Step 4.  State your conclusion.
 
12.   Now test the claim of a tobacco company spokesmen that people in the ETS population have "positive" levels of cotinine (significantly greater than zero), suggesting that this measure is not a good indicator of exposure to tobacco smoke. Use a significance level of 0.05. 

Step 1.  Determine parameter of interest and compose null and alternative hypotheses.
 
Step 2.  Determine the sample mean, sample standard deviation, and sample size.  [Hint:  You did this in an above step in this assignment.]
 
Step 3.  Determine the likelihood that the population mean is actually equal to 0 by completing a Hypothesis Test: One Mean in STATDISK.   Use significance of 0.05.  Paste results here.
 
Step 4.  State your conclusion in terms of the claim by the tobacco company.
 

13.   Answer the following questions based on the above hypothesis test.


a.       What is the p-value in this example and what does it represent?
 
b.      Does the p-value need to be different in order for us to FAIL TO REJECT the null hypothesis here?

Submit your final draft to the Assignment 2 Turnitin – Week 4 area of your course. Please use the naming convention "WK4Assgn2+first initial+last name" as the Submission Title.
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