Answer:
Q1: 0.88015 ~ 88.015%, are
Q2: 0.88176 ~ 88.176%, are not
Explanation:
Okay so a simple way to do these probability ones is to add an extra space around each side
A B C D
ACCURATE 310 262 246 144 ___
NOT ACCURATE 31 51 37 12 ___
___ ___ ___ ___ ___
Now in these spaces add all the the rows and columns accordingly
A B C D
ACCURATE 310 262 246 144 _962_
NOT ACCURATE 31 51 37 12 _131_
_341_ _343_ _283_ _156_ _1093_
Now the number in the place where the additional rows meet is your total number of orders, so this is what you would use for your probability.
So we are looking for ACCURATE / ALL which is 962
Now do 962 divided by 1093 and your probability comes out to 0.88015, so as a percentage, would be 88.015%
With replacement, all variables become independent, however without replacing that changes the probability.
When the 2 orders are selected, the final number of probability changes - so it would take down the total each time, the find the mean or average of the probability for your answer.
So since there is no replacement for ACCURATE / ALL which is 962, the division instead would be by 1091, since we are taking 2 orders out and not putting them back, it brings down the total number by 2, which would make the probability come out to 0.88176, or 88.176%