Question
The amounts a soft drink machine is designed to dispense for each drink are normally distributed, with a mean of 12.3 fluid ounces and a standard deviation of 0.2 fluid ounce. A (a) Find the probability that the drink is less than 12.2 fluid ounces. (b) Find the probability that the drink is between 11.9 and 12.2 fluid ounces. (c) Find the probability that the drink is more than 12.7 fluid ounces. Can this be considered an unusual event? Explain your reasoning. (a) The probability that the drink is less than 12.2 fluid ounces is (Round to four decimal places as needed.)
Explanation / Answer
a) P(X<12.2) =P(Z<(12.2-12.3)/0.2)=P(Z<-0.5) =0.3085
b)P(11.9<X<12.2)=P((11.9-12.3)/0.2<Z<(12.2-12.3)/0.2) =P(-2<Z<-0.5) =0.3085-0.0228 =0.2858
c)P(X>12.7)=P(Z>(12.7-12.3)/0.2) =P(Z>2)=0.0228