Question

Thickness measurements of a coating process are made to the nearest hundredth of amillimeter. The thickness measurements are uniformly distributed with values 0.15, 0.16, 0.17, 0.18, and 0.19. Determine the mean and variance of the coating thickness for this process.A. mean (in millimeter).

B. variance (in millimeters^2).

Answer 1

Mean=
`0.17`
`mm`

Variance=
`2*10^(-4)`
`mm^(2)`

Explanation:

Given is the uniform distribution

x=0.15,y=0.19

where x and y are lower and upper values.

mean=(x+y)/2

mean=(0.19+0.15)/2

Mean=0.17 mm

Now using equation

variance =
`((b-a+1)^(2)-1) /12`

For variance take a=15,b=19

Variance=
`((19-15+1)^(2)-1)/12`

Variance=2
`*10^(-4)`
`mm^(2)`