pre statistics
posted by Angela .
In a recent health study it was claimed that 18% of americans are underwieght.If 4 americans randomly selected what is the probability that
a. that all will be underweight
b.none will be underweight
c. at least one will be underweight

pr(a.)=18/100*18/100*18/100*18/100
I will be happy to check the others. On the last, remember there are four ways the combination can occur 
Sorry, on the last, you could have
4 ways to have one underweight
UFFF, FUFF, FFUF, FFFU
Ways to have two U
UUff, UfUf, UffU, FUUf, FUfU, FfUU
Ways to have three U
UUUf, UfUU, FUUU, UUfU
Ways to have four U.
UUUU