# statistics/probability

posted by
**mary- please check calculations.**
.

in testing a new drug. researchers found that 20% of all patients using it will have a mild side effect. a random sample of 14 patients using the drug is selected. find the probability that:

a) exactly three will have mild side effects.

b) at least four will have this mild side effect.

*once again the more i work with numbers the more i get confused. please show calculations in detail. thank you.

mary hornbeck