You are an audit manager of David and Goliath Accounting Firm (DG) and listed some of substantive procedures you want to perform during the year end audit:

1. Select a sample of invoices and ensure that they have been properly recorded in the sales ledger.

2. Perform a debtors confirmation (a.k.a. accounts receivable circularisation).

3. Attend the year-end stocktake and perform test counts on a sample of stock items.

4. Calculate the accounts receivable turnover and compare with previous years turnover.

REQUIRED: Name the type of substantive audit procedure in EACH of the above and provide ONE key financial statement assertion to which it significantly relates.