You have been hired as the new controller for the Ralston Company. Shortly after joining the company in 2021, you discover the following errors related to the 2019 and 2020 financial statements:

1. Inventory at December 31, 2019, was understated by $6,100.
2. Inventory at December 31, 2020, was overstated by $9,100.
3. On December 31, 2020, inventory was purchased for $3,100. The company did not record the purchase until the inventory was paid for early in 2021. At that time, the purchase was recorded by a debit to purchases and a credit to cash.

The company uses a periodic inventory system. Required: 1. Assuming that the errors were discovered after the 2020 financial statements were issued, analyze the effect of the errors on 2020 and 2019 cost of goods sold, net income, and retained earnings. (Ignore income taxes.) 2. Prepare a journal entry to correct the errors.