The diameter of a virus is approximately 0.3 mm (micrometers). There is some speculation that new virus strains exhibit greater variability in diameter. A medical research lab obtained a random sample...

The diameter of a virus is approximately 0.3 mm (micrometers). There is some speculation that new virus strains exhibit greater variability in diameter. A medical research lab obtained a random sample of 15 new virus strains and measured the diameter (in mm) of each. The sample mean diameter was 0.323 and the sample variance was s 2 = 0.0026. Is there any evidence to suggest the true population variation in diameter of viruses has increased from 0.0015? Assume normality and use a = 0.05.

The radial shrinkage in paper birch wood from green to oven dry is approximately 6.3%. A new process has been developed to decrease the variability in shrinkage. In a random sample of 21 pieces of paper birch, the sample variance in shrinkage was 0.39. Is there any evidence to suggest the population variance in shrinkage is less than 0.50? Assume normality and use a = 0.10.