Final answer:
To correctly copy an entire worksheet in Excel, right-click the worksheet tab, select 'Move or Copy', choose the location, check 'Create a copy', and click 'OK'.
Step-by-step explanation:
To copy an entire worksheet and all its data in Excel, holding down SHIFT and dragging the selected sheet along the row of sheet tabs is not the correct method. Instead, you should right-click on the tab of the worksheet you want to copy, and select 'Move or Copy' from the context menu. In the 'Move or Copy' dialog box, you can then choose where to place the copy and make sure to check the 'Create a copy' checkbox before clicking 'OK' to complete the operation.