Question

The diameters of ball bearings are distributed normally. The mean diameter is 130 millimeters and the variance is 9. Find the probability that the diameter of a selected bearing is greater than 135 millimeters. Round your answer to four decimal places.

Answer 1

Answer:

0.0478

Step-by-step explanation:

We solve using z score formula

z = (x-μ)/σ, where

x is the raw score = 135 mm

μ is the population mean = 130 mm

σ is the population standard deviation.

We are given variance = 9

Standard deviation = √variance = √9 = 3

Hence

z = 135 - 130/3

z = 1.66667

Probability value from Z-Table:

P(x<135) = 0.95221

P(x>135) = 1 - P(x<135) = 0.04779

Approximately to 4decimal places = 0.0478