Open the Part view (table) at the desired project.

Click on Edit project in batch mode in the toolbar or in the context menu.

--> The same-named dialog opens.

All attributes of the selected project are listed.

Mark the desired attribute row in the dialog window.

Insert the desired value or value range into the Feature value field.

(Under Edit dataset you can see the original attribute values.)

Note Optionally you can set table restrictions. Then changes are only processed in all visible project rows.

Confirm with Ok.

Load the changed project and check the value range of the changed variable at different rows.

The displayed values are correct