Answer:
Option d) 840
Step-by-step explanation:
Given that a test to measure psychotic tendencies was given to a group of 1,000 air force cadets who wished to work in nuclear silos.
If Score ≥64 would be eliminated.
X is N(52, 12)
Probability for any random person to get eliminated
=[tex]P(X\geq 64)\\= 1-R(64)\\=1-0.8413\\= 0.1587[/tex]
Now coming to sample size of 1000 people, we find each person is independent of the other and there are two outcomes either >64 or < 64
So Y no of persons who get more than 64 is binomial with n =1000 and p = 0.1587
Mean of Y = E(Y)
= no of people who were not accepted [tex]=1000(0.1587) = 158.7[/tex]
No of people accepted [tex]= 1000-158.7 = 841.3\\=841[/tex]
Approximately we get 840 so option d
