Cheyenne Corp. reported these income statement data for a 2-year period. Cheyenne Corp. uses a periodic inventory system. The inventories at January 1, 2021, and December 31,20 the ending inventory at December 31,2021 , is overstated by $6,000. (a) Prepare correct income statement data for the 2 years. What is the cumulative eifect of the inventory error on total gross profit for the 2 years? Cumulative effect of the inventory error $