a computer programm contains one error.in order to find the error, we split the program in to blocks and test 2 of them,selected at random.let X be the numer of errors in these blocks.compute E(x)...
my solution:
probability of erro in 2 blocks= 1/2=0.5
now probability that there is no error in both blocks = 1-1/2=0.5

probability that there is atleast one error in both blocks= 1/2 +1/2=1

E(x)= 1
am i right?

Question

a computer programm contains one error.in order to find the error, we split the program in to blocks and test 2 of them,selected at random.let X be the numer of errors in these blocks.compute E(x)...
my solution:
probability of erro in 2 blocks= 1/2=0.5
now probability that there is no error in both blocks = 1-1/2=0.5

probability that there is atleast one error in both blocks= 1/2 +1/2=1

E(x)= 1
am i right?

anonymous · Answer

Does the question state how many blocks its split up into? 2?

anonymous · Answer

sorry .i mistyped.it says "it splits the program into 6 blocks.

dumbcow · Answer

if there are 6 blocks and you randomly select 2 of them then the probability the error is in 1 of the 2 blocks should be 1/3 not 1

anonymous · Answer

If the E(X) = 1 then that means it has a 100% which is incorrect. Each block has an equal probability to contain the error so 1/3 because you choose 2/6.

anonymous · Answer

alright thanks all of u