37% of college students say they use credit cards because of the rewards program. You randomly select 10 college kids and ask each to name the reason he or she uses credit cards. Find the probability that the number of college students who say they use credit cards because of the rewards program is (a) exactly two, (b) more than two, and (c) between two and five inclusive.

Answer 1

those who use it -- .37
those who don't --- .63

prob(exactly 2 out of 10 will use it)
= C(10,2) (.37)^2 (.63)^8 = .003397

b)
more than two ---> exclude cases of none, one, and two
prob = 1 - ( C(10,0)( .37)^0 (.63)10 + C(10,1) (.37)(.63)^9 + C(10,2) (.37)^2 (63)^8 )
= ...
you do the button pushing

c) repeate abvove method for
two cases + three cases + four cases + five cases

Answer 2

44% of adults say cashews are their favorite kind of nut. You randomly select 12 adults and ask each to name his or her favorite nut. Find the probability that the number who say cashews are their favorite nut is (a) exactly three, (b) at least four, and (c) at most two.