Table 7 The calculation results of t-test.
Material | Assumption | Levene test of variance equation | t-test pf mean–variance | |||||
|---|---|---|---|---|---|---|---|---|
F | Sig | t | df | sig（Bilateral） | Mean difference | Standard error | ||
C25 concrete | Variance is equal | 0.203 | 0.658 | -2.630 | 18.000 | 0.017 | -16.419 | 6.243 |
Variance inequality | – | – | -2.630 | 15.229 | 0.019 | -16.419 | 6.243 | |
C30 concrete | Variance is equal | 1.952 | 0.179 | -2.508 | 18.000 | 0.022 | -16.146 | 6.437 |
Variance inequality | – | – | -2.508 | 14.106 | 0.025 | -16.146 | 6.437 | |
HRB400 steel bars | Variance is equal | 2.718 | 0.117 | 4.201 | 18.000 | 0.001 | 297.914 | 70.921 |
Variance inequality | – | – | 4.201 | 13.633 | 0.001 | 297.914 | 70.921 | |
