This paper describes a convenient way of performing statistical tests in biology. The recent development of powerful spreadsheet programs for microcomputers has made it possible to easily apply various statistical significance tests on biological data. Presently the following tests have been implemented in the LOTUS 1-2-3 framework: Student's t-test, chi-square test, analysis of variance (single classification random ANOVA), Student-Neumann-Kuels test, correlation analysis and analysis of linear regression (single and multilevel design). The most important advantages gained by using 1-2-3 instead of the commercial statistical software packages are the simplicity of entering data, the possibility of asking "what-if?" questions, the simple, but useful graphical presentation of data and the ease of actual building of the tests.