Sam Sung is evaluating a new advertising program that could increase electronic sales. Possible outcomes and probabilities of the outcomes are shown below.

$\backslash$table$[[,$Additional$],[$Possible Outcomes,Sales in Units,Probabilities$],[$Ineffective campaign,$70,0\mathrm{.}20],[$Normal response,$145,0\mathrm{.}20],[$Extremely effective,$395,0\mathrm{.}60]]$

Compute the coefficient of variation. $($Do not round intermediate calculations. Round the final answer to $3$ decimal places.$)$

Coefficient of variation