From one newbie to another, don't sweat it. Actually this is an interesting topic.

I always had these ratios in mind (running:biking).

1:10 on the downhills
1:5 on the flats, no headwind
1:4 with rolling hills
1:3, on the flats with a moderate to strong headwind
1:2, on steep hills
1:1, on monster hills (like mountain biking)

No science to this; just my own experiences.

(FWIW -- I've been "promoted" to a Junior Member on this board. Yee haa !!!)