Trials are often made where the effects of one or several factors are investigated on a phenomenon. As soon as the trial results contain some degree of randomness, then the trials have to be planned so that the uncertainty in the results and the risk of erroneous decisions can be determined (significance level and strength function with hypothesis testing).
Many-factor trials, that is trials where the effects of several factors are studied at the same time, are quite useful when many factors can be expected to interact, that is the effect of varying one factor is dependent on the values of other factors. This is often the case for effects on measurement values and many-factor trials are therefore an effective way of optimising and validation measurement methods.
ISO 3534-3 Statistics – Vocabulary and symbols – Part 3: Design of experiments