E$7\mathrm{.}9$ Assume a restaurant owner is showing a positive operating income in $9$ of $12$ months of operation and is considering whether to close during $3$ months of the off$-$season. Given the information below, do you recommend he close or stay open the last $3$ months?

$\backslash$table$[[,9$ months,$3$ months,Total$],[$Sales revenue,$$378,{000}_{?},$$$22,{000}_{?},$$$400,{000}_{?}$