Question

The fracture strength of tempered glass averages 13.7 (measured in thousands of pounds per square inch) and has standard deviation 2. (a) What is the probability that the average fracture strength of 100 randomly selected pieces of this glass exceeds 13.9

Answer 1

0.15866

Explanation:

Given :

μ = 13.7

x = 13.9

Sample size, n = 100

Standard deviation, σ = 2

Recall:

Z = (x - μ) ÷ σ/√n

Z = (13.9 - 13.7) ÷ 2/√100

Z = 0.2 ÷ 0.2

Z = 1

P(x > 13.9) = p(Z > 1) = 0.15866