Question

A class has average height of 68 inches and a standard division of 2 inches what height do you need to be taller than 90% of the class please round your answer to the nearest thousandth.

Answer 1

65.426

Explanation:

Given that:

Mean height (m) = 68 inches

Standard deviation (s) = 2 inches

Height required to be taller than 90% of the class :

P(Z > x) = 0.9

The corresponding Zscore is - 1.282 (Z probability calculator)

Using the Zscore relation :

Zscore = (x - m) / s

-1.282 = (x - 68) / 2

-1.282 * 2 = x - 68

-2.564 = x - 68

-2.564 + 68 = x

x = 65.436