Shack Homebuilders Limited is evaluating a new promotional campaign that could increase home sales. Possible outcomes and probabilities of the outcomes are shown next.

$\backslash$table$[[,$Additional Sales,$],[$Possible Outcomes,in Units,Probabilities$],[$Ineffective campaign,$60,0\mathrm{.}40],[$Normal response,$80,0\mathrm{.}30],[$Extremely effective,$140,0\mathrm{.}30]]$

Compute the coefficient of variation.