SOLUTION: A company hires management trainees for entry-level sales positions. Past experience indicates that only 10% will still be employed at the end of 9 months. Assume the company recen
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Question 1183046: A company hires management trainees for entry-level sales positions. Past experience indicates that only 10% will still be employed at the end of 9 months. Assume the company recently hired 6 trainees.
a. What is the probability that three of the trainees will still be employed at the end of 9 months?
b. What is the probability that at least two of the trainees will still be employed at the end of 9 months?
c. What is the expected number of trainees that will still be employed at the end of 9 months?
d. What is the standard deviation of the number of trainees that will still be employed at the end of 9 months? Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! This is 6C3(0.1)^3*(0.9)^3
the 6C3 are the number of ways three may be chosen from 6 (20).
=0.01458
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Look at prob (0) and prob (1) and subtract that from 1. This will give the probability of at least 2. The prob. of 0 is .9^6=0.5314
1 is 6*.9^5*.1=0.3542
=0.8856
So the probability of at least two is 0.1144
E(X)=np =6*0.1=0.6 trainees
Var(X)=np(1-p)=0.6*0.9=0.54
sd is sqrt(V)=0.7348 trainees
