Question

A factory produces plate glass with a mean thickness of 4 mm and a standard deviation of 1.1 mm. A simple random sample of 100 sheets of glass is to be measured, and the mean thickness of the 100 sheets is to be computed. What is the probability that the average thickness of the 100 sheets is less than 3.74 mm

Answer 1

Answer:

0.0090483

Approximately = 0.00905

Step-by-step explanation:

z = (x - μ)/σ, where

x is the raw score = 3.74

μ is the sample mean = population mean = 4 mm

σ is the sample standard deviation

This is calculated as:

= Population standard deviation/√n

Where n = number of samples = 100

σ = 1.1/√100

σ = 1.1/10 = 0.11

z = (3.74 - 4) / 0.11

z = -2.36364

Using the z score table to determine the probability,

The probability that the average thickness of the 100 sheets is less than 3.74 mm

P(x<3.74) = 0.0090483

Approximately = 0.00905