BASIC GUIDELINE TO CONDUCT ONE-WAY ANOVA USING XLSTAT IN EXCEL: APPROACH TO CARIES DATA
Background: The One-Way ANOVA is commonly used to test statistical differences among the means of two or more groups or intervention or change score. There are two assumption are needed for this analysis such as normality distribution and randomness & independence. In ANOVA, multiple comparison methods are designed to investigate differences between specific pairs of means. This provides the information that is of most use to the researcher. The objective in this study is to provide basic guideline how to conduct one-way ANOVA analysis using XLSTAT Excel.
Materials and Methods: In this paper will explain how to conduct one-way ANOVA using XLSTAT software, an add on of Microsoft Ofﬁce Excel. Firstly, checking normality and secondly ANOVA analysis. Secondly, set up and interpret a one-way Analysis of Variance (ANOVA) followed by Bonferroni multiple comparisons in Excel using the XLSTAT software.
Result: We want to compare mean difference between smoker status relate with number of caries. In order to make a confident and reliable decision, we will need evidence to support our approach. This is where the concept of ANOVA comes into play. From Shapiro-Wilk test, as the computed p-value is greater than the significance level alpha=0.05, the caries data was extracted follows a Normal distribution. The Bonferroni test is applied to all pairwise differences between means. Based on the p-values (Pr>Diff), all pairs of smoking status appear to be significantly different effect on number of caries (heavy smoker vs non-smoker), (Heavy smoker vs ex- smoker) and (Ex-smoker vs non-smoker).
Conclusion: Heavy smoker vs non-smoker gives the higher mean difference = 9.8986 which can conclude that heavy smoker will increase the number of caries among patients compare to non-smoker patients. Besides that, heavy smoker vs ex-smoker is statistically significant difference effect on number of caries where heavy smoker is effect on number of caries compare with ex-smoker = 6.8986. XLSTAT is a powerful yet flexible Excel data analysis add-on that allows users to analyze, customize and share results within Microsoft Excel.
Keywords: One-Way ANOVA, XLSTAT software, Compare Means, Caries Data