How do I get the program to create a new rectangle that bounds the selected objects? Thanks.

Thanks! I had to amend that:

1. Copy the selected objects, Edit menu > Copy.
2. Draw a rectangular shape.
3. Paste the size of the objects from step (1) on the drawn rectangle, Edit menu > Paste Size > Paste Size.
4 Group the objects from step 1
5. Select the objects from step 1, then add-select the rectangle
6 In Align and Distribute with Relative to: First Selected, click Centre on vertical axis and center on horizontal axis

This succeeded in visual and geometric bounding box modes e.g.

here's another method, although I'm not sure it works in older versions of Inkscape.
1. Select the objects and group (ctrl-g),
2. make guides from the group (shift-g)*.
3. draw a rectangle snapping from the top left intersection of the guides to the bottom right intersection.

*In your preferences/tools you have to check both 'keep objects after conversion' and 'treat groups as a single object'

Thanks. That works here on 0.48. It does have the slight disadvantage of requiring manual placement method

> you have to check ... 'treat groups as a single object'

I find that unnecessary.