How likely is a bird to be classified as positive?

Question

(1) 80 percent of birds with avian flu are classified as positive.

(2) 5 percent of birds without avian flu are classified as positive.

Marcab · Answer

I doubt the OA.
Do also mention the source please.

Anichka · Answer

I got it from my course materials. I believe it is from Barrons - 2007 / Test 1, but I didn't find it on the internet. (this is what it is written on the Test materials as a source). I also doubt the OA and completely do not agree with it.

Bunuel · Answer

The answer to this question is E, not D. We need to know the percentage of birds with avian flu to answer the question.

NeetiGupta · Answer

Hi bunuel

This question looks very abstract . How can one define which bird is considered to be positive?

LalaB · Answer

overlapping sets question -

Avian flue // Non-avian flue
Positive 0.8 (TA) 0.05(NA)
not Positive
============================
 Total Avian flue(TA) //Total Non-avian flue

Positive =0.8TA+0.05Na 
since we dont know TA and NA, we cant find total positive

unceldolan · Answer

Lol strange question. Looked at it, went straight for E.

Reasoning: If there were 1000 birds, of which have 100 the avian flu, 80 would be positive and of the other 900 45 were positive. But since we don't know nothing about any total percents or numbers, we can't solve! Hence E. Pretty awkward though.

LogicGuru1 · Answer

The moment you see "How likely" ? you should realise that it is asking about Positive bird /Total Bird

Since Both the statments are talking about % values , we cannot calcualte the NUMBER of BIRDS
we dont know 80% of what (What is total number of birds in question)
same with statement 2

ANSWER IS E

sb0541 · Answer

Clearly statement 1 and 2 are insufficient on its own .
In order to answer this DS question , we should know what percentage of birds have avian flu . There is no information about this statistics .
So, the answer is E .

frndrobinster · Answer

Since the actual no. of birds having flue is no known, it is insufficient to answer the question even after combining two statements. 
Answer E

Mick1005 · Answer

IMO: E.
We need ratio of birds with Avian Flue and Birds with Non-Avain flu.

stne · Answer

Initially I thought C then while posting that query found out how its E ,below is the working , hope it helps.

how likely means probability !

Probability = Positive cases / Total cases

1) we have no idea of other positive cases , we know that 80% of avian flu are positive only , NS.
2) Here we have know idea of avian flu, positive cases , NS

1+2 covers all the cases , avian flu + non avian flu cases

let there be 100 + 100 cases , probability =85/200 =17/40
let there be 100 + 200 cases , probability=90/300= 3/10

Answer E.

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How likely is a bird to be classified as positive?

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How likely is a bird to be classified as positive?

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