SOLUTION: Suppose that the number of cars arriving at a busy intersection in a large city has a Poisson distribution with mean 120. Determine a lower bound for the probability that the numbe

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Question 1178273: Suppose that the number of cars arriving at a busy intersection in a large city has a Poisson distribution with mean 120. Determine a lower bound for the probability that the number of cars arriving in a given 20-minute period will be between 100 and 140 using Chebyshev’s inequality.
thank you

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
I'm assuming that the mean is for 20 minutes.
poisson has equal mean and variance, so variance is 120 and sd is sqrt(120)=10.954
The range is 20 on either side of the mean or 1.826 sd
The lower bound for the probability the number is in this range is 1-(1/1.826)^2=0.700.