Question

3.1.5. Over the years, the percentage of candidates passing an entrance exam to a prestigious law school is 20%. At one of the testing centers, a group of 50 candidates take the exam and 20 pass. Is this odd? Answer on the basis that X 220 where X is the number that pass in a group of 50 when the probability of a pass is 0.2.

Answer 1

We have given p=0.2

x is the number pass in a group of 50

X~ approximatellly normal (mean=10, variance =8)

we want to test getting 20 pass in group of 50 is odd or not

p(X>20)=p(z>(20-10)/sqrt(8))

=p(Z>3.5355)

=1-0.9997

=0.0003

Hence 20 pass in group of 50 is odd