Why do we reject the null hypothesis when we get a sample test statistic in the tail of its distribution if we can make an error in doing so?

What is the quadric regression equation that fits these data

Δabc is dilated by a scale factor of 3 with the origin as the center of dilation to form δa′b′c′. the slope of is -1.2. the length of is p units, the length of is q units, and the length of is r units. the slope of is . the length of is units.

17 in long 1.3 ft wide and 8in high what is the volume