Research Article
The Application of Response Surface Methodology in the Investigation of the Tribological Behavior of Palm Cooking Oil Blended in Engine Oil
Table 8
Estimated regression coefficients for COF.
| Term | Coef | SE Coef | -ratio | value |
| Constant | 0.337598 | 0.077232 | 4.371 | 0.022 | Speed | −0.000174 | 0.000520 | −0.335 | 0.760 | Load | −0.064568 | 0.006435 | −10.033 | 0.002 | Volume composition | 0.005517 | 0.002745 | 2.010 | 0.138 | Speed speed | 0.000002 | 0.000001 | 1.571 | 0.214 | Load load | 0.004496 | 0.000240 | 18.712 | 0.000 | Volume composition volume composition | 0.000039 | 0.000118 | −2.790 | 0.761 | Speed load | −0.000050 | 0.000018 | −2.790 | 0.068 | Speed volume composition | −0.000033 | 0.000012 | −2.667 | 0.076 | Load volume composition | 0.000236 | 0.000117 | 2.023 | 0.136 |
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