An article gave the following observations on maximum concrete pressure (kN/m2) 33.3 41.9 37.4 40.3 36.7 39.2 36.3 41.8
36.0 35.3 36.7 38.9 35.8 35.2 40.2
(a) Is it plausible that this sample was selected from a normal population distribution? Using a normal probability plot, we ascertain that it is plausible that this sample was taken from a normal population distribution. Using a normal probability plot, we ascertain that it is not plausible that this sample was taken from a normal population distribution. Because of the number of observations, we ascertain that it is not plausible that this sample was taken from a normal population distribution Because of the number of observations, we ascertain that it is plausible that this sample was taken from a normal population distribution
(b) Calculate an upper confidence bound with confidence level 95% for the population standard deviation of maximum pressure. (Round your answer to three decimal places.)