A manufacturer knows that 90% of its Zener diodes meet specifications (S). Suppo
ID: 3183309 • Letter: A
Question
A manufacturer knows that 90% of its Zener diodes meet specifications (S). Suppose diodes are repeatedly selected at random (assume independence). What is the probability that the 8th selected diode the 5th that meets specifications? (a) (8 3) 0.9^3 0.1^5 (b) (8 5) 0.9^5 0.1^3 (c) (7 4) 0.9^4 0.1^4 (d) (7 4) 0.9^5 0.1^3 (e) None of the above A server is pinged according to a Poisson process with mean rate lambda = 3 pings per second. What is the probability that the server is pinged 15 times in 5 seconds? (a) (e^-3 3^3/3!)^5 (b) (e^-3/5!)^3 (c) e^-3 3^15/15! (d) e^3^15/3! (e) None of the aboveExplanation / Answer
1. Here probability of success is p=0.9 so q=0.1
Here n=8 and x=5
So P(x)=ncxp^x(1-p)^n-x=8c5(0.9)^5(0.1)^3
Hence b is answer