Provides neutrosophic analysis of variance (NANOVA) and analysis of covariance (NANCOVA) for Completely Randomized Designs (CRD) and Randomized Complete Block Designs (RCBD) using interval-valued observations. Computes interval sums of squares, mean squares, F-statistics, significance tests, and interval-based least significant difference (LSD) comparisons. When lower and upper observations are identical (crisp data), the methods reduce to the corresponding classical ANOVA and ANCOVA.