STAT3510 W2023 TermTest1 Version 1

pdf

School

University of Guelph *

*We aren’t endorsed by this school

Course

3510

Subject

Statistics

Date

Feb 20, 2024

Type

pdf

Pages

Uploaded by MateMoon13191

STAT*3510: Environmental Risk Assessment Term Test #1 VERSION A Friday, February 17, 2023 (12:30pm-1:20pm) Name: Student Number: This test contains 4 double-sided pages (including this cover page), plus 1 single-sided page of R output. Please check this now! There are 5 written response questions, with allotted marks for each question indicated beside the question number. There are a maximum of 20 marks available. You are permitted one letter-size (8.5” X 11”), double-sided, HAND WRITTEN (no typing, photocopying, etc.) reference sheet, along with a stand-alone calculator. No other resources are permitted. Please write your answer in the space provided. Show all of your work. Answers that are correct but have no work shown will receive a grade of 0. All numeric results should be given to 4 decimal places where appropriate. 1

Name: Student Number: 1. (5 marks) A multiple linear regression model was used to investigate whether metabolic rate ( Metab , measured in KJ/day) was a useful predictor of lifespan ( Life , measured in years) for mammal species, after adjusting for the mammal’s bodymass ( Mass , measured in kg). Two linear regression models were fit to the data, and the resulting partial R output is available on the page labelled Mammal Lifespans . Use the provided output to answer the questions below. Note: To improve model fit, both the variables Life and Mass were log-transformed. For ease of interpretation, you can simply refer to these variables by their original names. (a) Is the interpretation of ˆ β 0 meaningful in either Model 1 or Model 2? Briefly explain why / why not. (b) A platypus has a metabolic rate of 229 KJ/day with a bodymass of 1.30 kg. What is the estimated mean log-lifespan, based on Model 1? CONTINUED ON NEXT PAGE 2 of 8

Name: Student Number: (c) Make a conclusion regarding the usefulness of metabolic rate as an explanatory variable for lifespan, after adjusting for bodymass. Justify your response using relevant values from the output. 3 of 8

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Name: Student Number: 2. (3 marks) A study was conducted to determine if a relationship exists between being placed into foster care as a young child and graduating from high school. A researcher used court records to identify 900 children who were placed into foster care at a young age (12 years or younger), and then identified another 1000 children with similar demographic characteristics that had not been placed in foster care. Using information from subsequent years of high school records, the researcher was able to determine how many individuals in each group had eventually graduated high school. (a) What type of observational study is this: cross-sectional, cohort, or case-control? (b) Consider the sentence “... with similar demographic characteristics ...”. Why do you think this part of the study design was necessary? Provide an example of a demographic characteristic that the researcher may hold similar between the two groups to support your argument. 4 of 8

Name: Student Number: 3. (3 marks) During an investigation of the U.S. space shuttle Challenger disaster, it was learned that the project managers had judged the probability of mission failure to be 0.00001, whereas engineers working on the project had estimated the probability of failure to be 0.005. Calculate both the risk difference and releative risk of mission failure in the engineers versus the project managers 1 . Which risk metric do you think would be better to describe the discrepancy in perceived risk between the engineers and the project managers? Briefly explain why in 2 - 3 sentences. 1 You can think of mission failure as being the outcome of interest, and engineer/non-engineer as being the exposed/unexposed groups, if that is helpful. 5 of 8

Name: Student Number: 4. (6 marks) A study was conducted to investigate if ginkgo biloba reduced the risk of developing Acute Mountain Sickness (AMS) among individuals trekking in the Himalayans. Researchers randomly assigned 119 Trekkers to receive a placebo and 124 Trekkers to receive ginkgo biloba. The results of the study are displayed in the table below: Placebo Ginkgo biloba Total AMS 79 81 160 No AMS 40 43 83 Total 119 124 243 (a) Determine the baseline risk for developing AMS. (b) Determine the relative risk of developing AMS for individuals that received ginkgo biloba compared to those that received the placebo. Provide an appropriate interpretation of the value you have calculated. CONTINUED ON THE NEXT PAGE 6 of 8

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Name: Student Number: (c) Calculate a 90% confidence interval for the true value of the relative risk. Based on this interval, does it seem that ginkgo biloba is effective at reducing the risk of AMS? Justify your response. To aid in your calculations, use the fact that SE ( ln ( d RR )) = 0 . 09239. Some of the following values from R may be useful: qnorm(0.90)=1.282 qnorm(0.95)=1.645 qnorm(0.975)=1.960 7 of 8

Name: Student Number: 5. (3 marks) The following data are the results of a study involving breast cancer and the amount of alcohol consumed per week: Breast Cancer No Breast Cancer < 4 drinks per week 330 658 ≥ 4 drinks per week 204 386 The researchers are interested in if there is a decreased risk of breast cancer associated with consuming less alcohol per week. (a) Which test: Chi-Square Test for Independence, a test for the difference in two population proportions, or Fisher’s Exact Test, is most appropriate for the researchers’ investigation? Briefly explain your choice. (b) Suppose we were to analyze this data with a test for the difference in two population proportions. What would be the corresponding null and alternative hypotheses? Note: make sure your mathematical notation is defined! 8 of 8

Related Documents

STAT-1000---Worksheet-9---Shell.pdf

Week_8_Assignment_ITCS_6216.docx

My findings when analyzing the number of returns by state.docx

Activity #8 Correlation & Regression (AU23 in-person).doc

hw2sol.pdf

L01ab Submit - HW 1 SRA 365.pdf

Lab05_Simple_Regression.docx

STA4164 Assignment 1 S24 (1).docx

Discussion forum unit 2.docx

Data Sciene Extra Credit.pdf

Chapter-Quizzes-28ymha7.docx

mparvez2023-DataScience Assignment 3.ipynb - Colaboratory.pdf

Recommended textbooks for you

Elementary Algebra

Algebra

ISBN:9780998625713

Author:Lynn Marecek, MaryAnne Anthony-Smith

Publisher:OpenStax - Rice University

Algebra: Structure And Method, Book 1

Algebra

ISBN:9780395977224

Author:Richard G. Brown, Mary P. Dolciani, Robert H. Sorgenfrey, William L. Cole

Publisher:McDougal Littell

Holt Mcdougal Larson Pre-algebra: Student Edition...

Algebra

ISBN:9780547587776

Author:HOLT MCDOUGAL

Publisher:HOLT MCDOUGAL

Mathematics For Machine Technology

Advanced Math

ISBN:9781337798310

Author:Peterson, John.

Publisher:Cengage Learning,

SEE MORE TEXTBOOKS

Recommended textbooks for you

Elementary Algebra
Algebra
ISBN:9780998625713
Author:Lynn Marecek, MaryAnne Anthony-Smith
Publisher:OpenStax - Rice University
Algebra: Structure And Method, Book 1
Algebra
ISBN:9780395977224
Author:Richard G. Brown, Mary P. Dolciani, Robert H. Sorgenfrey, William L. Cole
Publisher:McDougal Littell
Holt Mcdougal Larson Pre-algebra: Student Edition...
Algebra
ISBN:9780547587776
Author:HOLT MCDOUGAL
Publisher:HOLT MCDOUGAL
Mathematics For Machine Technology
Advanced Math
ISBN:9781337798310
Author:Peterson, John.
Publisher:Cengage Learning,