Gold miners in Alaska have found on average 12 ounces of gol

Gold miners in Alaska have found, on average, 12 ounces of gold per 1000 tons of dirt excavated with a standard deviation of 3 ounces. Assume the amount of gold found per 1000 tons of dirt is normally distributed. Refer to Exhibit 6-2. What is the probability the miners find more than 16 ounces of gold in the next 1000 tons of dirt excavated?

Solution

Normal Distribution
Mean ( u ) =12
Standard Deviation ( sd )=3
Normal Distribution = Z= X- u / sd ~ N(0,1)                  
P(X > 16) = (16-12)/3
= 4/3 = 1.3333
= P ( Z >1.333) From Standard Normal Table
= 0.0918