Find the upper and lower z-values that would give you the middle 90% of the area under the curve.

Question

Find the upper and lower z-values that would give you the middle 90% of the area under the curve. (Hint: the two values are the same but one is positive and one is negative)

Answer 1

Nick,

       You have to find a table of the area of the normal curve then find the 90% point. The answer is lower z=-1.645 and upper z = 1.645 the normal curve is symmetric.

Jim