I am confused on the correction for overstatement

*Exercise 4-9 Presented below is information related to Sheridan Corp. for the year 2017 Net sales Cost of goods sold Selling expenses Administrative expenses Dividend revenue Interest revenue $1,385,200 785,900 69,400 51,600 25,900 7,360 Write-off of inventory due to obsolescence Depreciation expense omitted by accident in 2016 Casualty loss Cash dividends declared Retained earnings at December 31, 2016 Effective tax rate of 34% on all items $82,320 48,800 54,100 41,270 988,070