A study was conducted among patients with retinitis pigmentosa, an ocular condition where pigment appears over the retina, resulting in substantial loss of vision in many cases. The study was based on 94 patients who were seen annually at a baseline visit and three annual follow-up visits. In this study, 90 patients provided visual-field measurements at each of the four examinations and are the subject of the following data analyses. Visual field was transformed to the natural logarithm (ln) scale to better approximate normality and yielded the data given in the table below:Assuming that a change in visual field over 3 years is normally distributed when using the ln scale, what is the proportion of patients who showed a decline in visual field over 3 years?What percentage of patients would be expected to show a decline of at least 20% in visual field over 3 years? (Note: In the ln scale this is equivalent to a decline of at least ln (1/0.8) = 0.223).What percentage of patients would be expected to show a decline of at least 50% in visual field over 3 years? AutoSaveHome Insert Draw Design LayoutPastePage 2 of 2Times New... V 12 vB I U451 wordsA Aab x₂x² AvReferencesAa ✓English (United States)+Vi.Mailingsii.iii.Review ViewE-VVYear of examinationYear 0 (baseline)Year 3Year 0Year 3* In (area of visual field) in degrees squared.Developer→ 2↓Mean*8.158.010.143A study was conducted among patients with retinitis pigmentosa, an ocular condition wherepigment appears over the retina, resulting in substantial loss of vision in many cases. The studywas based on 94 patients who were seen annually at a baseline visit and three annual follow-upvisits. In this study, 90 patients provided visual-field measurements at each of the fourexaminations and are the subject of the following data analyses. Visual field was transformed tothe natural logarithm (ln) scale to better approximate normality and yielded the data given in thetable below:Tell meAaBbCcDdEeNormalAaBbCcDdEe Aa BbCcDc AaBbCcDdE€ AaBbNo SpacingHeading 1Standard deviation1.231.330.66Heading 2N909090Assuming that a change in visual field over 3 years is normally distributed whenusing the In scale, what is the proportion of patients who showed a decline in visualfield over 3 years?What percentage of patients would be expected to show a decline of at least 20% invisual field over 3 years? (Note: In the In scale this is equivalent to a decline of atleast In (1/0.8) = 0.223).What percentage of patients would be expected to show a decline of at least 50% invisual field over 3 years?FocusTitleCommentsAaBbCcDd EeSubtitleStylesPaneIEditingDictateShare ✔Editor+ 150%

Given the data asYear of examinationMean*Standard deviationNYear 0 (baseline)8.151.2390Year…

Answered: A study was conducted among patients…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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A study was conducted among patients with retinitis pigmentosa, an ocular condition where pigment appears over the retina, resulting in substantial loss of vision in many cases. The study was based on 94 patients who were seen annually at a baseline visit and three annual follow-up visits. In this study, 90 patients provided visual-field measurements at each of the four examinations and are the subject of the following data analyses. Visual field was transformed to the natural logarithm (ln) scale to better approximate normality and yielded the data given in the table below:

Assuming that a change in visual field over 3 years is normally distributed when using the ln scale, what is the proportion of patients who showed a decline in visual field over 3 years?
What percentage of patients would be expected to show a decline of at least 20% in visual field over 3 years? (Note: In the ln scale this is equivalent to a decline of at least ln (1/0.8) = 0.223).
What percentage of patients would be expected to show a decline of at least 50% in visual field over 3 years?

AutoSave
Home Insert Draw Design Layout
Paste
Page 2 of 2
Times New... V 12 v
B I U
451 words
A A
ab x₂x² A
v
References
Aa ✓
English (United States)
+
V
i.
Mailings
ii.
iii.
Review View
E
-
V
V
Year of examination
Year 0 (baseline)
Year 3
Year 0
Year 3
* In (area of visual field) in degrees squared.
Developer
→ 2↓
Mean*
8.15
8.01
0.14
3
A study was conducted among patients with retinitis pigmentosa, an ocular condition where
pigment appears over the retina, resulting in substantial loss of vision in many cases. The study
was based on 94 patients who were seen annually at a baseline visit and three annual follow-up
visits. In this study, 90 patients provided visual-field measurements at each of the four
examinations and are the subject of the following data analyses. Visual field was transformed to
the natural logarithm (ln) scale to better approximate normality and yielded the data given in the
table below:
Tell me
AaBbCcDdEe
Normal
AaBbCcDdEe Aa BbCcDc AaBbCcDdE€ AaBb
No Spacing
Heading 1
Standard deviation
1.23
1.33
0.66
Heading 2
N
90
90
90
Assuming that a change in visual field over 3 years is normally distributed when
using the In scale, what is the proportion of patients who showed a decline in visual
field over 3 years?
What percentage of patients would be expected to show a decline of at least 20% in
visual field over 3 years? (Note: In the In scale this is equivalent to a decline of at
least In (1/0.8) = 0.223).
What percentage of patients would be expected to show a decline of at least 50% in
visual field over 3 years?
Focus
Title
Comments
AaBbCcDd Ee
Subtitle
Styles
Pane
I
Editing
Dictate
Share ✔
Editor
+ 150%

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

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