Sub groups Main groups N Mean SD t-value p-value Sub group 1 Group 1 5 156.38 42.69 -9.6006 0.0000*   Group 2 5 558.68 83.41     Sub group 2 Group 1 15 384.39 55.77 0.7082 0.4847   Group 2 15 369.89 56.43     Sub group 3 Group 1 15 279.05 31.78 2.0252 0.0525   Group 2 15 241.56 64.26     *p< 0.05 t test: student t test

Table 2: Comparison of Group 1 and Group 2 with Respect to Fracture Toughness in all Sub Groups by T Test