Youngkwon C. answered 02/05/16
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Knowledgeable and patient tutor with a Ph.D. in Electrical Eng.
Hi James,
In case of a normal distribution,
a standard/normalized value can be obtained according to the following formula
z = (Z - μ)/σ
where Z is a sample value to be normalized.
In this problem, as Z = 68.5
z = (68.5 - 63.5)/2.5
= 5.0/2.5
= 2.0