<PRE><B>Question 198561</B>
The owner reports 20% of the customers entering the store will make a purchase of at least $50. Suppose 15 customers enter the store before 10am on a particular Saturday 
a) How many of these customers would you expect to make a purchase of at least $50?
Ans: 0.20*15 = 3
----------------------------
b) What is the probability exactly five of these customers make a purchase of at least $50?
Ans: 15C5(0.2)^5(0.8)^10 = 0.1032
---------------------------------------------------
c) What is the probability at least five of these customers make a purchase of at least $50?
Ans 1 - binomcdf(15,0.2,4) = 0.16423....
---------------------------------------------------
d) What is the probability at least one customers make a purchase of at least $50?
Ans: 1 - binomcdf(15,0.2,0) = 0.96482...
============================================
Cheers,
Stan H. 



</PRE>