$($b$)$ A customer has called back with a revised order. Rather than use materials that cost $$$$33$ per$$ unit, the customer prefers to use a cheaper material that reduces the cost to $$$$1\mathrm{.}801\mathrm{.}80.$ Based on the fit of the indicated$$ model, how should this reduction affect the average cost per unit$$ ordered? Give your answer as a$95\%$ confidence interval.