posted by aaron .
The unemployment rate is 5.8% (Bureau of Labor Statistics, April 3, 2003). Suppose that 100 employable people are selected randomly.
1)What is the probability that exactly six people are unemployed (to 4 decimals)?
2)What is the probability that exactly six people are unemployed (to 4 decimals)?
3)What is the probability that at least four people are unemployed (to 4 decimals)?
An excel spreadsheet is very helpful
for these kinds of calculations.
You could calculate these pobabilities directly. Or, you could use a poisson distribution. I'll use a Poisson here.
the formula for the poisson is
P(k;l) = (l^k)*e^(-l) / k!
where l is the expected number = 5.8
and k is the observed number.
so for 1 (and 2, they are identical)
P(k;l) = 5.8^6 *e^(-5.8) / (1*2*3*4*5*6)
take it from here.