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Old 03-13-2013
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Stats Mean, Median, Mode

As a part of a study to determine factors influencing mortality in an intensive care unit, serum creatinine concentrations (in mg/dL) are obtained from 10 consecutive patients at the time of admission to the intensive care unit. The results are shown in the graph. Which of the following statements regarding the sizes of the mean, median, and mode of the serum creatinine values is correct?

A. The mean is larger than the median
B. The median is larger than the mean
C. The median is larger than the mode
D. The mode is larger than the median
E. The mean, median, and mode cannot be determined because the distribution is not normal (gaussian)

Mean, Median, Mode-0000000.jpg
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Please explain the answer...
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  #2  
Old 03-13-2013
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A is my answer.

correct me if im wrong.
the 10 values are - 0.5 0.5 0.5 1 1 1 1 2 4 5

mean - 8.3
MOde (MOst number) - 1
MEDian (MIDdle number) - in this case 1+1/2 = 1.
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Old 03-13-2013
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Negative skew it looks like

SO the answer is C. Median > mode.

MAY BE WRONG

Last edited by mdsoon; 03-13-2013 at 01:32 PM.
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Old 03-13-2013
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Quote:
Originally Posted by mdsoon View Post
Negative skew it looks like

SO the answer is C. Median > mode.

MAY BE WRONG
If it is negative skewd , isn't it gonna be Mode > median > mean???

While positive skewed will be Mean > Median > mode ???

So if thats the case , the answer should be D.
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Old 03-13-2013
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if it is positive skew option A and D are correct.
if it is negative skew option B and D are correct.

yes/no?
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Old 03-13-2013
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now 'im even more confused

so whats the right answer?
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Old 03-13-2013
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i think its A based on my calculation. but i dont know if thats the right method to use.
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Old 03-13-2013
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Listening PLZ help

I don't know the answer. I think A might be correct, but some believe that B might be correct. This is a NBME Q. http://www.usmleforum.com/files/forum/2009/1/444772.php
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Old 03-13-2013
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that post was made in 2005 and still nobody knows the answer.. LOST CAUSE MAYBE..


take it as a WFT question and move on.
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Old 03-13-2013
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Quote:
Originally Posted by Evergreen View Post
As a part of a study to determine factors influencing mortality in an intensive care unit, serum creatinine concentrations (in mg/dL) are obtained from 10 consecutive patients at the time of admission to the intensive care unit. The results are shown in the graph. Which of the following statements regarding the sizes of the mean, median, and mode of the serum creatinine values is correct?

A. The mean is larger than the median
B. The median is larger than the mean
C. The median is larger than the mode
D. The mode is larger than the median
E. The mean, median, and mode cannot be determined because the distribution is not normal (gaussian)

Attachment 3079
click image to enlarge

Please explain the answer...
This is negative skewed. General: Mode > Median > Mean. Specific: Median > Mean. And this is what they look for - Specific. Therefore, the answer shall be B.
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THE ANSWER IS B, because negatively skewed plots the median is greater than the mean
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Quote:
Originally Posted by samren17 View Post
if it is positive skew option A and D are correct.
if it is negative skew option B and D are correct.

yes/no?
I agree!
Which makes me think maybe the last choice us correct?
So i looked up whats Gaussian distribution, only found out that its the normal distribution, which contradicts whats mentioned in that last choice =s

http://hyperphysics.phy-astr.gsu.edu/%E2%80%8Chbase/math/gaufcn.html#c2

http://www.thefreedictionary.com/_/dict.aspx?word=Gaussian+distribution
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Old 03-13-2013
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@doctor ali - what is the "specific: - is it a medical term used in these graph situations or something else?

@faith - well your work of looking it up paid off as something right.im done for today.see you guys tomoro.
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A. The mean is larger than the median

I believe that's the right answer. The plot/graph given is not a frequency plot; I mean the y-axis is not the frequency of ppl who have a certain creatinine value, it's the actual raw value of their creatinine level. We simply add up the values and divide by 10 (total number of ppl/values to get the mean), and of course the median is the value in the middle in ascending order.

If instead of having creatinine concentration on the y-axis, we had number of ppl (frequency), and we had on the x-axis creatinine values. Then this graph would be negatively skewed, and mode>median>mean could apply.
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Last edited by slowpoke; 03-13-2013 at 09:47 PM.
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Old 03-14-2013
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Default alaskaa

Quote:
Originally Posted by Evergreen View Post
As a part of a study to determine factors influencing mortality in an intensive care unit, serum creatinine concentrations (in mg/dL) are obtained from 10 consecutive patients at the time of admission to the intensive care unit. The results are shown in the graph. Which of the following statements regarding the sizes of the mean, median, and mode of the serum creatinine values is correct?

A. The mean is larger than the median
B. The median is larger than the mean
C. The median is larger than the mode
D. The mode is larger than the median
E. The mean, median, and mode cannot be determined because the distribution is not normal (gaussian)

Attachment 3079
click image to enlarge

Please explain the answer...
is their any one who can tell the right ans even i m thinking for a
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Old 03-14-2013
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Quote:
Originally Posted by samren17 View Post
@doctor ali - what is the "specific: - is it a medical term used in these graph situations or something else?

@faith - well your work of looking it up paid off as something right.im done for today.see you guys tomoro.

I mean general speaking vs. specific speaking.

In negative skewed:
General speaking: Mode > Median > Mean
Specific speaking: Median > Mean

In positive skewed:
General speaking: Mean > Median > Mode
Specific speaking: Mean > Median

In most cases, they want specific speaking answers.
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Biostatistics-Epidemiology, Figures-, Step-1-Questions

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