Question

1. The bore diameters of a sample of randomly selected bearings are shown here (in mm): 50.001, 50.002, 49.998, 50.006, 50.005, 49.996, 50.003, 49.997, 49.999, 50.004.
   Construct and interpret a normal probability plot of these bore diameters.
   Does the assumption that bore diameters for this bearing is well modeled by a normal distribution seem reasonable?

Answer 1

In order to solve this question I used R software.

R codes and output:

x=c(50.001, 50.002, 49.998, 50.006, 50.005, 49.996, 50.003, 49.997, 49.999, 50.004)
> qqnorm(x)
> qqline(x)

From normal probability plot we see that all the points line very close to straight line except the first and last point.

Which implies the assumption that bore diameters for this bearing is well modeled by a normal distribution seem to be reasonable.