The following results were obtained when each of a series of standard silver solutions was analyses by flame atomic-absorption spectrometry. Concentration, ng mL-' 10 15 20 25 30 Absorbance 0.003 0.127 0.251 0.390 0.498 0.625 0.763 a. Determine (present answers using both manual calculations and Excel generated result) the slope and intercept of the calibration plot, and their confidence limits at 95%. b. Estimate the limit of detection of the silver analysis.