Selector Tool - Scaling Field
The Scaling field on the Selector Tool Infobar is used to scale the selection. Entering a value into the field and pressing RETURN scales the currently selected objects.
The Aspect Ratio Lock button to the right of the Scaling Field locks the aspect ratio of the selected objects. What this means is changing one of the scaling vales will change the other by an equal amount so the objects are the same shape. This lets you scale objects without distorting them. To scale just the width or height of the selection, turn aspect ratio off.
The scaling is centered around the transformation center. This will usually be in the center of the selection unless it has been moved.