Avobenzone is one of the active ingredients in several commercially available sunscreens. It can be absorbed into the bloodstream when sunscreen is applied to the skin. The Food and Drug Administration has expressed concern about the safety of absorbing too much avobenzone. Researchers recruited 24 healthy volunteers to investigate avobenzone absorption for four different commercially available sunscreens: two sprays, a lotion, and a cream. Do the types of sunscreens (spray, lotion, and cream) differ in terms of how much avobenzone is absorbed into the blood? Subjects were randomly assigned to one of the four sunscreens, with six subjects for each. Subjects had 2 milligrams of sunscreen per 1 cm? applied to 75% of their body surface area (area outside of normal swimwear) four times per day for four days. The amount of avobenzone absorbed into the bloodstream (in nanograms per milliliter ap-plied, ng/mL) after 150 hours was then measured for each subject. For the purpose of analyzing the data us ing ANOVA, the logarithms of the measurements were used. Thus, for example, a value of 0 corresponds to an absorption of 1 ng/ mL and negative values correspond to absorptions less than 1 ng/ mL. Larger values of the logarithms correspond to larger levels of absorption. Figure 27.13 shows JMP ANOVA output for these data. a. Do these data satisfy the conditions for ANOVA? b. State Ho and H. for the ANOVA F test and explain in words what ANOVA tests in this setting. c. Report your overall conclusions about whether the types of sunscreen differ in the mean amount of avobenzone absorbed into the bloodstream after 150 hours.

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question

Avobenzone is one of the active ingredients in several commercially available sunscreens. It can be absorbed into the bloodstream when sunscreen is applied to the skin. The Food and Drug Administration has expressed concern about the safety of absorbing too much avobenzone. Researchers recruited 24 healthy volunteers to investigate avobenzone absorption for four different commercially available sunscreens: two sprays, a lotion, and a cream. Do the types of sunscreens (spray, lotion, and cream) differ in terms of how much avobenzone is absorbed into the blood? Subjects were randomly assigned to one of the four sunscreens, with six subjects for each. Subjects had 2 milligrams of sunscreen per 1 cm? applied to 75% of their body surface area (area outside of normal swimwear) four times per day for four days. The amount of avobenzone absorbed into the bloodstream (in nanograms per milliliter ap-plied, ng/mL) after 150 hours was then measured for each subject. For the purpose of analyzing the data us ing ANOVA, the logarithms of the measurements were used. Thus, for example, a value of 0 corresponds to an absorption of 1 ng/ mL and negative values correspond to absorptions less than 1 ng/ mL. Larger values of the logarithms correspond to larger levels of absorption.

Figure 27.13 shows JMP ANOVA output for these data.

a. Do these data satisfy the conditions for ANOVA?

b. State Ho and H. for the ANOVA F test and explain in words what ANOVA tests in this setting.

c. Report your overall conclusions about whether the types of sunscreen differ in the mean amount of avobenzone absorbed into the bloodstream after 150 hours.

 

 

imp
Oneway Anova
4 Analysis of Variance
Source
Group
Error
3
20
C. Total 23
DF Sum of Squares Mean Square
1.55286
0.43361
Level
4 Means and Std Deviations
Number
Cream
Lotion
Spray 1
Spray 2
4.658577
8.672101
13.330678
Std Dev
6 -0.915479 0.6297893
0.2225703 0.7306505
6
6 0.0804044 0.6380284
6 -0.30336 0.6299645
Mean
F Ratio
3.5813
Prob > F
0.0320*
0
X
Std Err Mean
Lower 95%
Upper 95%
-1.576402 -0.254556
0.2571104
0.2982868 -0.5442 0.989341
0.260474 -0.589165 0.7499741
0.2571819 -0.964467 0.3577474
Transcribed Image Text:imp Oneway Anova 4 Analysis of Variance Source Group Error 3 20 C. Total 23 DF Sum of Squares Mean Square 1.55286 0.43361 Level 4 Means and Std Deviations Number Cream Lotion Spray 1 Spray 2 4.658577 8.672101 13.330678 Std Dev 6 -0.915479 0.6297893 0.2225703 0.7306505 6 6 0.0804044 0.6380284 6 -0.30336 0.6299645 Mean F Ratio 3.5813 Prob > F 0.0320* 0 X Std Err Mean Lower 95% Upper 95% -1.576402 -0.254556 0.2571104 0.2982868 -0.5442 0.989341 0.260474 -0.589165 0.7499741 0.2571819 -0.964467 0.3577474
Spray 1
Spray 2
Lotion
Cream
0.693 0.405 0.405 0.405
-0.511 -0.916
0.588 0.000
0.000 -0.511 -0.693 - 1.204
1.386 0.693 0.182
0.095 -0.511 -0.511
-0.357 -0.357 -0.357 -1.204 -1.609 -1.609
Transcribed Image Text:Spray 1 Spray 2 Lotion Cream 0.693 0.405 0.405 0.405 -0.511 -0.916 0.588 0.000 0.000 -0.511 -0.693 - 1.204 1.386 0.693 0.182 0.095 -0.511 -0.511 -0.357 -0.357 -0.357 -1.204 -1.609 -1.609
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps

Blurred answer
Follow-up Questions
Read through expert solutions to related follow-up questions below.
Follow-up Question

Based on the data in both images. show how the values are acquired. 

Solution
Bartleby Expert
SEE SOLUTION
Similar questions
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman