ISRO2018-48

Question

In unit testing of a module, it is found that for a set of test data, at the maximum $90$% of the code alone were tested with the probability of success $0.9$. The reliability of module is

1. Greater than $0.9$
2. Equal to $0.9$
3. At most $0.81$
4. At least $0.81$

Comments

similar question 

https://gateoverflow.in/48978/isro2014-23

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https://gateoverflow.in/56262/ugcnet-june2012-iii-30

Answer 1

In Unit testing of the module, at the max 90% of the code was tested (0.9)

Probability of success  = 0.9

Reliability = 0.9 * 0.9 = 0.81

Answer is at the most 0.81 since it is given that at the max 90% code was tested . Hence Option C 

Comments

Sir,

In the question it is not given that 90% of the code is tested. 

The question is at maximum 90% of the code is tested.

Now, suppose only 70% of the code is tested where the probability of sucess is 0.9 then what should be the reliability of the module.

I think the answer is 0.7 * 0.9 = 0.63 < 0.81.

So, in the answer there should be at most 0.81.

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yes, I missed that.

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Sir

how 100% failure?

we even not think about it

It is a simple probability question

Cases should be

Success       Failure

1)  T      T

2)   T                F

3)    F               T

4)    F                F

And we only think about 1st case

no other case we need to consider