Display y-value when pointing

[geoffL]

How do I set up a chart so that when I hover the cursor over the line it displays the y-value?

[EarnestAl]

To see tooltip data labels I think you need:

1. to be in Edit mode for the graph
2. to have Points (and lines) for line graphs. Bar and Column show by default

You could, in Edit mode, right click each line and select Insert data labels which will be visible in normal mode