A shaft manufacturing company is having a permissible variance of 9mm2 in the diameter of manufactured shafts. A sample of 10 shafts is to be tested, what is the permissible upper limit of standard...

A shaft manufacturing company is having a permissible variance of 9mm2 in the diameter of manufactured shafts. A sample of 10 shafts is to be tested, what is the permissible upper limit of standard deviation for the sample at α = 0.05?