Bartosiewicz Clinic uses client-visits as its measure of activity. During January, the clinic budgeted for 5,400 client-visits, but its actual level of activity was 5,420 client-visits. The clinic has provided the following data concerning the formulas used in its budgeting and its actual results for January: Data used in budgeting: Fixed element per month Variable element per client- visit $37.40 Revenue Personnel expenses Medical supplies Occupancy expenses Administrative expenses Total expenses $29,400 1,700 10,400 6,900 $48,400 $13.40 7.40 1.00 0.50 $22.30 Actual results for January: Revenue $150,400 Personnel expenses $ 70,100 Medical supplies $ 20,228 Occupancy expenses $ 14,110 Administrative expenses $ 7,590 The activity variance for net operating income in January would be closest to