Here is an example.

I want to adjust the scale of a clip on the timeline.

I have created a scale object on the timeline.

I can adjust it using the slider, although the increments available to me are too large and imprecise -- they let me change the scale from, for example, .76 to .66; but I would like the scale set to .71.

When I click the field (i.e. box) showing the numeric value, a blue frame appears around the field; but there is no response when I try to type a number in.

Any advice?

Double click the box to the side of the scale. You can enter your coordinates there.
Have fun.

Thanks Wes, but when I wrote that

"when I click the field (i.e. box) showing the numeric value [which is the box beside the scale], a blue frame appears around the field; but there is no response when I try to type a number in"

I am saying that I've tried what you suggest, but I can't actually enter the any numbers

Does it make a difference if you use the numbers on the keyboard vs. the numeric keypad?

That did it, thank you Axe