Copy of 2024_Winter_PH 7B HW3.docx

pdf

School

University of California, Riverside *

*We aren’t endorsed by this school

Course

Subject

Statistics

Date

Feb 20, 2024

Type

pdf

Pages

Uploaded by CommodoreFangHummingbird12

PH 7B Public Health Statistics II Homework 3 Question 1 (5pts). The slope of a regression line (y on x) is -0.24, we know that SDy=3.2 and SDx=4.0, then the correlation coefficient between the two variables is: A. 0.3 B. -0.3 C. 0.8 D. -0.8 Explain: = −0.24×4.0 3.2 = −0.96 3.2 = − 0. 3 Question 2 (5 pts) . A study has showed that the regression equation for predicting height from weight is: Predicted Height = (0.05 inches per pound) * (weight) + 65 inches If someone puts on 10 pounds, he will get taller by 0.05 * 10 = 0.5 inches. True or False: Explain: This is false because the association does not indicate causation, other factors, and limitations may affect the actual outcome. Question 3 (15 pts) . The following information was collected in a statistics class in Public Health. Average midterm score = 70, SD = 10 Average final score = 55, SD = 20 r= 0.50 SHOW YOUR WORK TO GET FULL CREDITS. 1) Final the regression equation for predicting the final score from the midterm score. a=Yˉ−b×Xˉ a=55−1.00×70a=55−1.00×70 a=−15a=−15 Y=−15+1X 2) How would you interpret the slope in this question? b =0.5×(20/10)=1

PH 7B Public Health Statistics II Homework 3 Slope = 1 this indicates that for every one-unit increase in the midterm score, the predicted final score is expected to increase by 1 unit. 3) For a student who got 75 in midterm, what is his predicted final score? (show two ways for the solution) Y=−15+1X Y=−15+1×75 1. Y=−15+75=60 2. 55+0.50x(20/10)x(75−70)=60 For a student who got 75 in the midterm, the predicted final score is 60. Question 4: (25 pts). An investigator has collected information from a sample of 5 diabetes patients regarding their daily exercise time and body mass index (BMI). (For practice purpose, use n=5 for all related calculations) Daily exercise time (in minutes) Body mass index (kg/m2) 30 24.5 42 25.6 15 30.6 50 26.9 64 25.2 1) Applying the least squares method to calculate the regression equation to predict BMI (kg/m2) based on daily exercise time (minutes). Show your work to get full credits (keep two decimal places). y=-0.08+29.78 2) Interpret the intercept and the slope. Slope:-0.08 Intercept: 29.78

PH 7B Public Health Statistics II Homework 3 3) Calculate the r.m.s error. What does the r.m.s error tell you? The r.m.s. error is 1.71. this tells me that a typical point on a graph will be above/below the regression. 4) A new patient with similar characteristics compared to the study sample has reported no exercise everyday, what is her predicted BMI based on the above equation? Her predicted BMI based on the question above is 29.78 𝑘𝑔/𝑚 2 5) Another new patient (with similar characteristics as the study sample) has reported a daily exercise time around 300 minutes, will you be able to predict her BMI? Explain why or why not. Her BMI can be calculated, however, it can not be used to predict her BMI. The calculation is -0.08(300)+29.78=5.78. Based on this, making a prediction would be would be difficult due to the inaccuracy.

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

Related Documents

Empirical Homework Submit.docx

psci200_finalexam_2023_A-L.pdf

psci200_finalexam_2023_M-Z(1).pdf

five.pdf

Stat230-Midterm_2023W1 - Solution.pdf

2024_Winter_PH 7B HW2.docx-2.pdf

Week5OGLHypothesisTesting.docx

Assignment Follow Up 2 - Dilpreet Singh.docx

Lab 2.docx

Analysis of Bernoulli.docx

M.Baker_ABA634_SAFMEDS_WEEK1.docx

M.Baker_ABA632_BLACKBOARDCOLLABORATE_week1.docx

Recommended textbooks for you

Functions and Change: A Modeling Approach to Coll...

Algebra

ISBN:9781337111348

Author:Bruce Crauder, Benny Evans, Alan Noell

Publisher:Cengage Learning

College Algebra

Algebra

ISBN:9781305115545

Author:James Stewart, Lothar Redlin, Saleem Watson

Publisher:Cengage Learning

Glencoe Algebra 1, Student Edition, 9780079039897...

Algebra

ISBN:9780079039897

Author:Carter

Publisher:McGraw Hill

Algebra & Trigonometry with Analytic Geometry

Algebra

ISBN:9781133382119

Author:Swokowski

Publisher:Cengage

Algebra and Trigonometry (MindTap Course List)

Algebra

ISBN:9781305071742

Author:James Stewart, Lothar Redlin, Saleem Watson

Publisher:Cengage Learning

Big Ideas Math A Bridge To Success Algebra 1: Stu...

Algebra

ISBN:9781680331141

Author:HOUGHTON MIFFLIN HARCOURT

Publisher:Houghton Mifflin Harcourt

SEE MORE TEXTBOOKS

Recommended textbooks for you

Functions and Change: A Modeling Approach to Coll...
Algebra
ISBN:9781337111348
Author:Bruce Crauder, Benny Evans, Alan Noell
Publisher:Cengage Learning
College Algebra
Algebra
ISBN:9781305115545
Author:James Stewart, Lothar Redlin, Saleem Watson
Publisher:Cengage Learning
Glencoe Algebra 1, Student Edition, 9780079039897...
Algebra
ISBN:9780079039897
Author:Carter
Publisher:McGraw Hill
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:9781133382119
Author:Swokowski
Publisher:Cengage
Algebra and Trigonometry (MindTap Course List)
Algebra
ISBN:9781305071742
Author:James Stewart, Lothar Redlin, Saleem Watson
Publisher:Cengage Learning
Big Ideas Math A Bridge To Success Algebra 1: Stu...
Algebra
ISBN:9781680331141
Author:HOUGHTON MIFFLIN HARCOURT
Publisher:Houghton Mifflin Harcourt