Question

Salmonellosis outbreak. Improperly handled or undercooked poultry and eggs are the most frequent cause of salmonella food poisoning. Salmonellosis can be deadly, although most individuals recover on their own. Cases must be reported to the CDC, where they are closely monitored. The average number of salmonellosis cases per month in South Dakota is 1.6. Let X be the monthly count of salmonellosis cases in South Dakota. a) Identify an appropriate probability distribution model for X. b) Find the mean and standard deviation of X. Round to 2 decimal places mean = standard deviation = c) The mean and standard deviation of salmonellosis cases in South Dakota over a six month period are mean = standard deviation = (Round to 2 decimal places)

Answer 1

since expected number of salmonellosis cases per month is fixed and can be assumed independent from trail to trail,

this can be approximated as Poisson distribution model with parameter =1.6

b)

mean = =1.6
standard deviation =√ =√1.6 =1.26

c)

for 6 months: mean =t =1.6*6 =9.6

and standard deviation = √t =√9.6 =3.10