First, make sure that both cursors are activated and are bound to the same curve. Then, if you want to compute the mean based on the static range between the cursors, just click on “Insert mean value” in the Analysis toolbar. An analysis object, which computes the mean based on the current cursor positions, is then added to the explorer.
To compute the mean dynamically based on changing cursor positions, you click on “Copy range(s)” in the Cursor menu. Select the option “Use variable for cursor positions”. Then activate the Explorer and click on “Paste” in the Edit menu. A formula, which reflects the dynamic signal range between the cursors, is then added to the Explorer. Now click on “Insert mean value” to compute the mean value of the range. If you change the cursor positions afterwards, then the analysis objects return value changes accordingly.