A Simple Method for Comparing Designs…Are Two Data Sets Significantly Different?

Research into data set comparison indicates that the likelihood ratio (LR) test with adjustment provides accurate confidence level results even for very small data sets. Inclusion of an unbiasing factor to modify the standard LR test for sample size appears to be the best available method for determining whether significant difference exists between data sets such as measurements from two separate designs. This modified LR test is tailored for Weibull data sets, but provides relatively unbiased results for normal and lognormal data sets as well. Two other methods, (1) viewing likelihood contour plots and (2) comparing double confidence bounds, also look promising. Further research is outlined.