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sum and averages

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by sumasajja » Sun Aug 07, 2011 4:15 am
THIRTY HOSPITAL PATIENTS WHO HAD BEEN TREATED FOR THE SAME ILLNESS WERE GIVEN A NEW TREATMENT IN THE RESEARCH STUDY .THEY WERE THEN ASKED TO EVALUATE IF THE SYMPTOMS FROM THE TREATMENT GOT BETTER OR WORSE
THE RATINGS WERE AS FOLLOWS
2: MUCH BETTER
1:SOMEWHAT BETTER
0:NEITHER BETTER OR WORSE
-1:SOMEWHAT WORSE
-2:MUCH WORSE

symptom , SUM OF 30 RATINGS , standard deviation of 30 ratings


H , 12 , 1.40
L , 35 , 0.69
P , -33 , 0.79
T , -26 , 0.43
V ,2 , 0.89

based on the sum of the ratings alone , how many of the symptoms must have had at least a rating of -2?
1]NONE
2]ONE
3]TWO
4]THREE
5]FOUR
Last edited by sumasajja on Sun Aug 07, 2011 5:16 am, edited 2 times in total.
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Source: — Problem Solving |

by sumasajja » Sun Aug 07, 2011 4:56 am
the answer to the problem is [spoiler]option 2
[/spoiler]
but i don't know the correct procedure, any1 please explain that.
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by GmatKiss » Sun Aug 07, 2011 5:06 am
Hi sumasajja,

symptom SUM OF 30 RATINGS

H 12
L 35
P -33
T -26
V 2

can you elaborate on the information above!
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by gmatboost » Sun Aug 07, 2011 10:24 pm
My interpretation is that, if all 30 ratings had been -1, a disease would have had a sum of -30. So, to be sure it got at least one -2, it must be below -30.

Having said that, this isn't very GMAT-like. Especially the listing of standard deviations.
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