Figure 2. Mean Variance Standard Uncertainty Deviation 0.21551 0.0014025 | 0.0074901 0.0193 Figure 2 shows the mean, variance, standard deviation and uncertainty values derived from the twenty-five sample hardness values. Figure 3. 0.193 0.201 0.208 0.216 0.123 0.23 0.239 Figure 3 represents the normal distribution graph of the hardness values determined during the experiement of a metal sample with a ninety-five percent probability