Question

The heights of students in a 5^th grade class are normally distributed with mean height 45 inches and standard deviation 5 inches. The students are divided into groups of 3. What height is such that the probability that the total height for a given group exceeds that height is 5%?

Answer 1

Solution :  

= 45

= / n = 5 / 3

P(Z > 1.645) = 0.05

z = 1.645

= z * + = 1.645 * 5 / 3 + 45 = 49.75

Height = 49.75 inches