- #1
logicaljoe
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Three drugs: A, B and C
50 subjects reported relief from:
21 drug a
21 drug b
31 drug c
9 a&b
14 a&c
15 b&c
41 report relief from at least one drug
Note that some of the subjects who reported results from A might have done so for B and C etc.
a. How many got relief from none of the drugs?
I assume I use the difference rule here
50 - 41 = 9 subjects that didn't report any relief.
b. How many people got relief from all 3 drugs?
D[A intersection B intersection C] = 21 + 21 + 31 - 9 - 14 - 15 = 35
such that 41 - 35 = 6 The number of subjects relieved by all three drugs.
c. How many subjects got relief from A only?
I'm kind of unsure about this question.
D[A - (A intersection B) - (A intersection C)]
So how do I identify the specific users that have ticked in both a int b and a int c?
21 - 9 - 14 + 6 = 4
This is all I can think off.
50 subjects reported relief from:
21 drug a
21 drug b
31 drug c
9 a&b
14 a&c
15 b&c
41 report relief from at least one drug
Note that some of the subjects who reported results from A might have done so for B and C etc.
a. How many got relief from none of the drugs?
I assume I use the difference rule here
50 - 41 = 9 subjects that didn't report any relief.
b. How many people got relief from all 3 drugs?
D[A intersection B intersection C] = 21 + 21 + 31 - 9 - 14 - 15 = 35
such that 41 - 35 = 6 The number of subjects relieved by all three drugs.
c. How many subjects got relief from A only?
I'm kind of unsure about this question.
D[A - (A intersection B) - (A intersection C)]
So how do I identify the specific users that have ticked in both a int b and a int c?
21 - 9 - 14 + 6 = 4
This is all I can think off.