has part has_specified_input has_specified_output achieves_planned_objective is denoted by has value statistical test hypothesis statistical hypothesis test objective data transformation false positive rate skewness probability distribution two tailed test 0 Added following a term request by Chris Mungall: https://github.com/ISA-tools/stato/issues/6 Alejandra Gonzalez-Beltran For example, we may wish to compare the mean of a sample to a given value x using a t-test. Our null hypothesis is that the mean is equal to x. A two-tailed test will test both if the mean is significantly greater than x and if the mean significantly less than x. The mean is considered significantly different from x if the test statistic is in the top 2.5% or bottom 2.5% of its probability distribution, resulting in a p-value less than 0.05. Orlaith Burke Philippe Rocca-Serra a two tailed test is a statistical test which assess the null hypothesis of absence of difference assuming a symmetric (not skewed) underlying probability distribution by allocating half of the significance level selected to each of the direction of change which could explain a difference (for example, a difference can be an excess or a loss). adapted from: http://www.ats.ucla.edu/stat/mult_pkg/faq/general/tail_tests.htm two sided test absence of negative difference hypothesis absence of positive difference hypothesis p-value ready for release