The statistical test developed by R.A. Fisher is: (A) Anova (B) Chi - square test (C) Z - test (D) Sign test Correct Ans: (A) Explanation: R.A. Fisher developed the ANOVA (Analysis of Variance) test, a statistical method used to analyze the differences among group means in a sample. Fisher designed ANOVA to help researchers identify if there are statistically significant differences between the means of three or more groups. ANOVA partitions the total variation in the data into components, which helps researchers determine whether the variations within or between groups are significant. This method allows for comparing multiple groups simultaneously, offering greater efficiency and accuracy in statistical analysis. In ANOVA, researchers calculate the F-statistic to compare the variation between groups to the variation within groups. If the F-statistic exceeds a certain threshold, researchers reject the null hypothesis, which assumes no significant difference between group means. ANOVA has become a widely used test in fields like agriculture, psychology, and medicine. It allows researchers to analyze experimental data and make informed conclusions about group differences. Fisher’s development of ANOVA revolutionized how we analyze and interpret data in experimental research.