If Agent Requests Proposal, What Does it Mean?

Hi everyone. Okay, this may be a silly question. I'm a previously published non-fiction author (twice), but I've never used an agent (nor tried to get one). For my third book, however, I think an agent is imperative.

So I just sent out about 25 email queries (not proposals) for the third non-fiction book. I've done it in waves, with the first dozen or so sent about 2 weeks ago, the second wave about 1 week ago.

The good news is that I've received 8 responses so far in which the agents have asked to see the full book proposal. I of course sent the proposal to them via email right away (as they all indicated they'd prefer).

Okay-- here are my questions: Since I've never used an agent before,

1. What does it mean when an agent asks for your full proposal? Does this indicate strong interest or just cursory interest? How "significant" is this?

2. How long should I expect the agent to take before deciding whether to represent me, once the proposal has been received? Is this a 2 week thing, a month-long thing, or a 6 month thing?

3. If anyone out there has had a similar experience, what do you think are the odds of landing an agent based on 8 requests for the proposal? Does it bode well that 8 are looking at the proposal? Do you think my chances are good of getting an agent?

Thanks for all your input!

Thanks SO much for the insight! This waiting for a "yes" or "no" is just the worst, isn't it? I feel like I'm glued to my email, waiting for the answer to arrive in my inbox! Or maybe they'll call if they want to represent me? Any thoughts on this? All communications have previously been in email, but I think I read elsewhere that if an agent wants to rep you, they'll call. Maybe I should go make sure my cell is charged.....