Answer:
0.070
Step-by-step explanation:
Y = number on trial
Y has a negative binomial distribution
r = 3
P = 30% = 0.3 probability of positive indication.
P(Y = 11) probability of 11 employees that must be tested to get 3 positives
Y-1Cr-1*p^r*q^(y-r)
Y-1 = 11-1 = 10
r-1 = 3 -1 = 2
10C2 x 0.3³x0.7⁸
45x0.027x0.05764801
= 0.070
This is the probability that 11 employees must be tested to get 3 positives.
Multipy 3 by 6 multiply 1 by 4 and 7 by 4 then add the numbers
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