SOLUTION: The average diameter of sand dollars on a certain island is 4.00 centimeters with a standard deviation of 0.60 centimeters. If 16 sand dollars are chosen at random for a collection

Algebra ->  Probability-and-statistics -> SOLUTION: The average diameter of sand dollars on a certain island is 4.00 centimeters with a standard deviation of 0.60 centimeters. If 16 sand dollars are chosen at random for a collection      Log On


   

Question 1089629: The average diameter of sand dollars on a certain island is 4.00 centimeters with a standard deviation of 0.60 centimeters. If 16 sand dollars are chosen at random for a collection, find the probability that the average diameter of those sand dollars is more than 3.85 centimeters. Assume that the variable is normally distributed.
a. 0.659

b. 0.780

c. 0.341

d. 0.841
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
z=(xbar-mean)/sigma/sqrt(n)
z>-0.15/0.60/sqrt(16)=-0.15*4/0.60
z>= -1
That is 0.8413
D.