Develop an empirical equation that represents the pump head (ft) as a function of capacity (gpm) for a Bell & Gossett Series e-80 2 × 2 × 7B pump with a 6½-inch impeller operating at 1750 rpm. The equation should be valid from 40 to 160 gpm.

Estimate the percent accuracy in the calculated pump head from the correlated equation by developing a deviation plot.