A variable is normally distributed with mean 68 and standard deviation 10.
a. Determine and interpret the quartiles of the variable.
b. Obtain and interpret the 99th percentile.
c. Find the value that 85% of all possible values of the variable exceed.
d. Find the two values that divide the area under the corresponding normal curve into a middle area of 0.90 and two outside areas of 0.05. Interpret your answer.