An analyst needs to evaluate the potential effect of an interferent, I, on the quantitative analysis for an analyte, A$.$ She begins by measuring the signal for a sample in which the interferent is absent and $[$A$]=15\mathrm{.}0$ ppm and obtains a mean signal of $24\mathrm{.}3.$ When she analyzes a sample in which the analyte is absent and $[$I$]=75\mathrm{.}0$ ppm$,$ she obtains a mean signal of $12\mathrm{.}7.$ a$.)$ What is the sensitivity for the analyte $($kA$)?$ b$.)$ What is the sensitivity for the interferent $($kI$)?$ c$.)$ What is the selectivity coefficient for this method $($KA$,$I$)?$ d$.)$ Calculate the signal of a sample if it is composed of $[$A$]=10\mathrm{.}0$ ppm and $[$I$]=20\mathrm{.}0$ ppm$.$ e$.)$ If $[$A$]$ is $10\mathrm{.}0$ ppm$,$ what is the maximum $[$I$]$ if the error in the signal must be less than $1\%?$