B) one of the coins used to calculate the regression equations has a gold content of 0.31%. calculate the residual for this coin. be sure to use correct notation and units.

The solution for this problem would be computed by:
There are 2 such coins (0.31, 0.17) and (0.31, 0.19). Their residuals are the given which are 0.17 – 0.2192 =0.0492 and 0.19 – 0.2192 would be equal to - 0.03 this would be the answer for this question.

This question doesn’t make any sense