Method of determining at least one tolerance band limit value (k, k p, k c) for a technical variable (x) under test, comprising: obtaining (S10, S10p, S10c, S20) the at least one tolerance band limit value (k, k p, k c) from sample tolerance band limit values of different samples, wherein the samples comprise values (z) of the technical variable (x) under test of the associated sample, wherein obtaining the at least one tolerance band limit value (k, k p, k c) comprises using a location measure (mean k, mean k p, mean k c) of a distribution according to which the sample tolerance band limit values (k, k p, k c) are distributed, wherein the technical variable (x) under test is distributed according to an underlying extreme value distribution function (F0, F9, F10), wherein each of the sample tolerance band limit values (k, k p, k c) is calculated (S6, S6p, S6c) by a processor (Pr) using a sample-specific conditional probability distribution function (F4, F11) which is a function of sample values (z) of the sample, wherein the technical variable (x) relates to a physical characteristic of a product that is producible in an industrial mass production process, and wherein the method further comprises: producing a lot of the products, taking a sample group of products from the lot, determining the values of the variable (x) under test for each product of the sample group, comparing the determined values with a tolerance interval that is calculated using the obtained tolerance band limit value (k p, k c), and deciding whether to accept the lot or to reject the lot based on the results of the comparison. obtaining (S10, S10p, S10c, S20) the at least one tolerance band limit value (k, k p, k c) from sample tolerance band limit values of different samples, wherein the samples comprise values (z) of the technical variable (x) under test of the associated sample, wherein obtaining the at least one tolerance band limit value (k, k p, k c) comprises using a location measure (mean k, mean k p, mean k c) of a distribution according to which the sample tolerance band limit values (k, k p, k c) are distributed, wherein the technical variable (x) under test is distributed according to an underlying extreme value distribution function (F0, F9, F10), wherein each of the sample tolerance band limit values (k, k p, k c) is calculated (S6, S6p, S6c) by a processor (Pr) using a sample-specific conditional probability distribution function (F4, F11) which is a function of sample values (z) of the sample, wherein the technical variable (x) relates to a physical characteristic of a product that is producible in an industrial mass production process, and wherein the method further comprises: producing a lot of the products, taking a sample group of products from the lot, determining the values of the variable (x) under test for each product of the sample group, comparing the determined values with a tolerance interval that is calculated using the obtained tolerance band limit value (k p, k c), and deciding whether to accept the lot or to reject the lot based on the results of the comparison. producing a lot of the products, taking a sample group of products from the lot, determining the values of the variable (x) under test for each product of the sample group, comparing the determined values with a tolerance interval that is calculated using the obtained tolerance band limit value (k p, k c), and deciding whether to accept the lot or to reject the lot based on the results of the comparison.