Stockton Ltd. changed its inventory system from FIFO to average cost. What type of accounting change does this represent?

1. A change in accounting estimate for which the financial statements for the prior periods included for comparative purposes do not need to be restated.
2. A change in accounting policy for which the financial statements for prior periods included for comparative purposes do not need to be restated.
3. A change in accounting estimate for which the financial statements for prior periods included for comparative purposes should be restated.
4. A change in accounting policy for which the financial statements for prior periods included for comparative purposes should be restated.