The manager of a lumber yard wants to assess the performance of a saw mill that cuts beams that are supposed to be 100 cm long. The manager takes a sample of 50 beams from the saw mill and measures their lengths.
The manager performs a 1 variance test to determine whether the standard deviation of the saw mill is different from 1.
Because a previous analysis showed that the data does not appear to come from a normal distribution, the manager uses the confidence interval for the Bonett method. The 95% confidence interval shows that a likely range for the population standard deviation of the length of all beams is 0.704 cm and 1.121 cm. A likely range for the population variance is 0.496 cm and 1.257 cm. Because the p-value is greater than 0.05, the manager cannot conclude that the population standard deviation is different from 1.