When the parameters of a population are known, the likelihood of obtaining a certain mean value, ¯ x , from a small sample can be predicted by the z‐variable with z = ( ¯ x − x ' ) / σ / √ n . consider a stamping process in which the applied load has a known true mean of 400 n with standard deviation of 25 n. if 25 measurements of applied load are taken at random, what is the probability that this sampling will have a mean value between 390 and 410?