The guys above are pretty much right, but to try and explain:
Domain authority, if you don't already know is really just an indicator of the total number of links and unique domains linking to your site (as opposed to just a single page). The more domains the better and works very similarly to PR.
Here's a Whiteboard Friday on Domain Authority and Trust - http://www.seomoz.org/blog/whiteboard-friday-domain-trust-authority - (about 7:45 fo DA)
And here's the Whiteboard Friday on how that's used in the SEOmoz tools - http://www.seomoz.org/blog/whiteboard-friday-domain-authority-page-authority-metrics - (part 2, round about the 8 minute mark, but worth watching it all).
Now, your question about whether linking out to pages effects DA we need to think about how PR works (as it's kinda the same) and as shown in the first video it doesn't matter how you interlink at the page level, but more the domain level. So links coming into your domain, on any page, determine your DA (to simplify it). And as such linking to low PA pages shouldn't have any effect.
Also linking out to other domains shouldn't effect your DA either and if I had to try and prove that I would probably turn to this YOUmoz piece from Hamlet batista - http://www.seomoz.org/blog/training-the-random-surfer-two-important-adjustments-to-the-early-pagerank-model - which is not as easy to digest, but if we assume DA works like PR then there's be little to no benefit in cutting those links out.
If you are worried about how you link then you may get some advantage from is streamlining the pages by consolidating them. Have a read of this and see if it helps - http://www.seomoz.org/blog/link-consolidation-the-new-pagerank-sculpting
Also, the best way to improve your site's DA is to build links from more domains wherever possible into these pages with low PA.
I'm going to publish this and have a read in case I need to edit or have wandered off topic, but hopefully it's useful for you