A company is experimenting with synthetic fibers as a substitutefor natural fibers.
The quality characteristic of interest is the breaking strength.A random sample of 8 natural fibers yields an average breakingstrength of 540 kg with a standard deviation of 55 kg. A randomsample of 10 synthetic fibers gives a mean breaking strength of 610kg with a standard deviation of 22 kg.
(a) Can you conclude that the variances of the breakingstrengths of natural and synthetic fibers are different? Use alevel of significance α of 0.05.
(b) Find a two-sided 95% confidence interval for the ratio ofthe variances of the breaking strengths of natural and syntheticfibers.
