STATISTICAL EVALUATION OF CUTANEOUS IRRITANTS 819

82O JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table II Analysis of Variance Source of Variation DF SS MS F' Between concentrations (A) 1 Between types of patch (B) 1 Between contact times (C) 1 Between observation times (D) 1 Concentration X patch type (AB) Concentration X contact time (AC) 1 Concentration X observation time (AD) 1 Patch type X contact time (BC) 1 Patch type X observation time (BD) 1 Contact time X observation time (CD) 1 Concentration X pressure X contact time (ABC) 1 Concentration X pressure X observation time (ABD) 1 Concentration X contact time X observation time (ACD) 1 Prcssure X contact time X observation time (BCD) Among replicates ABCD (within replicates, between blocks) Between block differences Total among blocks Residual (error) Total 1 2 1 2 __ I•l I__[ __ 47 o. 5208 o. 0469 9.6302 o. 1875 o. 7500 o. 0208 o. 1302 o. 1302 o. 02o8 o. 1875 o. 0208 o. 6302 0.0469 0. 0000 12.3228 8.0026 1 1719 3 7109 0.5208 0.0469 9 6302 0 1875 0 7500 0 0208 0 1302 0 1302 0 O2O8 0 1875 0 0208 0 6302 0.0469 0.0000 4.0013 1.1719 1.8555 12 8854 2.5771 6 5366 0.2335 31 7448 ... 2.23 1 41.24 1 3.21 1 1 1 1 1 1 2.70 1 1 2.16 1 . . . Sig. (P)'* Notes: (1) All main effects and interactions except ABCD tested against residual. (2) ABCD and replicates tested against the "between block differences M.S." (3) Definitions of column head symbols: DF = degrees of freedom, SS = sum of squares of deviations from the mean, MS = mean square, F' = value obtained in F test of significance, and P = probability of the observed difference having occurred by chance. "This column shows the probability that the given effect is not real. If P (probability of Ho or unreality) was over about 0.15, no entry was made in this column and the effect was considered "not significant."