SOLUTION: An internal study by the Technology Services department at Lahey Electronics revealed company employees receive an average of 3.5 non-work-related e-mails per hour. Assume the arri

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Question 1202769: An internal study by the Technology Services department at Lahey Electronics revealed company employees receive an average of 3.5 non-work-related e-mails per hour. Assume the arrival of these e-mails is approximated by the Poisson distribution.
a. What is the probability Linda Lahey, company president, received exactly 4 non-work-related e-mails between 4 p.m. and 5 p.m. yesterday?
b. What is the probability she received 6 or more non-work-related e-mails during the same period?
c. What is the probability she received four or less non-work-related e-mails during the period?

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
for 4 it is e^(-3.5)*3.5^4/4!=0.1888
for more than 6 it is 1-poisson cdf(3.5,6)=0.0653
for 4 or fewer it is
0.1888 for 4
0.2158 for 3
0.1850 for 2
0.1057 for 1
0.0302 for 0
0.7254 is the answer