Question

Question 20 A factory produces plate glass with a mean thickness of 4mm and a standard Type numbers in the boxes. deviation of 1.1mm. A simple random sample of 100 sheets of glass is to be 10 points 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? Round your answers to 5 decimal places.

Answer 1

Solution:

μ=4, σx=1.1

$\frac{\sigma_{x}}{\sqrt{n}}=\frac{1.1}{\sqrt{100}}=0.11$$σx/\sqrt{n}=1.1/\sqrt{100}=0.11$

σ=0.11

We have to find P($\bar{x}$<3.74)=...?

X - μ Z= 3.74 - 4 0.11 = 2.3636 o

P(Z<-2.3636) = 0.00905 ... Using normal z-table

Done