you should measure the final earning. ctr and impressions will change with refresh rate.
My own sense is that your revenue will remain generally the same - independent of the refresh rate (because statistically it makes no difference to first degree of approximation - secondary effects might be there). However some here have reported better results with shorter refresh rate like 45 seconds - while others have talked about “never” for refresh rate (or longest they could set it).
Your revenue may not look good for the impressions - but may not be bad for the download numbers (i.e. $7 for 200-300 downloads a day). In any case (according to the theory above) - the impressions alone will NOT be indicative of what you should earn - neither will eCPM be indicative of anything on it’s own. Since it is clear this can be directly affected by ramping up banner ad presentation rate (i.e. reduce “refresh rate” from 120 seconds to 45 seconds (say)).
You might consider using the measure introduced in this thread/post:
http://forums.makingmoneywithandroid.com/income-reports/3388-anyone-else-here-make-more-than-%2425k-day-2.html#post26711
Anyone else here make more than $25k a day?
For that you would require an estimate of session-length.
Although that metric assumes that admob banner + interstitials are shown (so your revenue may be slightly less if you are not including interstitials in your app).
Thanks. Actually my downloads have gone up for a past few days. Yesterday i had 7k downloads. Now total download count is 32k with 55% of them being active. I made only 12 dollars from that yesterday. 45k impressions, CTR 1,50% and RPM/eCPM 0.19
If the trend continues i am going to hit 50k in few days but i doubt i will earn more than 15 dollars per day on that. If thats normal i am OK with that but when i read some income reports of apps with similar impression/download/ctr figures and they are usually making 40-50 dollars a day.
Are you only using banners? You should try using interstitials too and you will at least double your income in most cases.
Only banner. I am gonna be n00b here and ask. What are interstitials? 
This blog post will surely be useful:
Why developers use interstitial ads to monetize iOS and Android apps
An interstitial is a full screen ad that can feature an array of different content.
AppWalls are a big one, where a list (usually scrollable) of Android Apps/Games are presented to the user. You are usually paid for any apps/games installed by your users through the wall.
General adverts are also very popular (Admob has a lot of these in their inventory) that pay on a CPC (cost per click) basis.
Video ads are also quite popular in certain types of apps/games.
There are other iterations of interstitials too, like “OfferWalls” or “Free App of the Day”.
These ad units are great to present during natural breaks in your app/game, including Launch and exit of the app/game. Obviously the placement is always down to you.
I highly recommend trying them out!
I’m seeing great results with Admob’s interstitials.
I have used AppBrain in the past with mixed results.
StartApp’s are also worth trying.
I have used mobileCore in the past too, but they’re results are really varied for me so I stopped using them.
These are just a few networks that offer them though, the list is pretty huge.
Like @dbest linked to you, there are many threads about them on the forum.
Thanks guys. You just opened a whole new world to me. Looks like there are some more reading to do. I should be developing my game no.2 now but learning all those tips and tricks, gathering info and trying to generate income is like another job her. Taking up most of my time. 
It is a profession in itself, even if you are not an indie.
While it might give you a headache at times, if you do things right your income will grow exponentially.
Always be ready to try different strategies and networks in different apps/games to see what works best.
Every app/game is different and most of the time you have a different audience too.
People behave differently to different ad types and setups.
Once you understand what works and why for your apps/games, you are golden.
Interstitials although harder to show frequently (because they take over the whole screen etc.) - so there are fewer opportunities to show them (while not pissing off users) - so most here would be showing them after you return from a menu screen back to the app (and that also timed so not appears more than once every 3 minutes - as one benchmark I would suggest).
So interstitial “impressions” (how many times they are shown) will be much lower than banner ads - however the revenue per impression (eCPM) will be much higher with interstitials which partly compensates that discrepancy. I am seeing nearly similar revenue from Admob interstitial vs. Admob banner ads. So banner ads make up for the low eCPM by the much bigger impression numbers (this is because banner ads are refreshing all the time and the user is unaware of them half the time - “banner blindness” - while it is harder to ignore an interstitial - esp. one with good ad copy i.e. which has a compelling message or similarity to user’s interests).
However, it also seems to be true that if you can DOUBLE your app’s download numbers with banner ads alone - then that will be similar (in revenue) to having both banner ads and interstitials.
So the question is does avoiding interstitials completely and only showing banner ad help an app (though users don’t generally complain if interstitials are less frequent than once per 3 minutes - from my experience - though occasionally someone will comment).
It could be argued that if your app has potential to be #1 in it’s niche - then perhaps not including interstitials may make the difference between being #1 and #5 or something (which may be 5x difference in downloads per day ?). I don’t have experience at that level of popularity to judge - but it is clear that many of the very popular apps seem to only have banner ads.
But for most developers - the addition of interstitials seems to match the banner revenue - and don’t seem to have much effect on user comments etc.
Read this thread about 2 months back and was excited to write here about my first App
was not knowing anything about Android 2 months ago. Though i come from strong C/C++/JAVA Background in Electronics domain.
give credit to all big developers here to guide and motivate at times.
My First App:-
Published : 2 weeks ago
Daily Installs : 600-950
Total Installs : 7500
Daily Revenue : $10
Definitely above stats are not impressive, but i made it finally gives me satisfaction and happiness
How did you promoted your app?
- $1k in appbrain
- multiple language support
- promotion in major forums
I have 3 free apps and 1 paid in Google Play, totaling under 200 downloads a day. I average around $0.40 a day with Greystripe. I show around 500 impressions per day, banner and full-page ads.
After reading all of the other posts, I must be doing something horribly wrong…
I have learnt that one can not start expecting the revenue and assume the success of your app/game soon after publishing in the Store. Its not like publish it and and money will start pouring. you have to do 2-3 times extra work to do publicity and understand the responces and give updates based on that.
personally i will divide the work as below.
Design - 20%
Coding -10%
Testing-15%
Marketing and updates - 55%
I make ±5$ per day, total amount of downloads is 4000, with absolutely no marketing
It varies and depends on how user takes your App/Game without marketing.
But marketing will always be helpful and work towards the good health of your Application.
sudden rise in revenue.
mine todays revenue is $16.2
it was between $8-10 untill now.
How i should take it? is it going to be stable or it was just a fluctuation?
Expect magic for Christmas. And in more exact words - makreters pay higher rates this period and users use apps more. 2+2 = harvest time for us. Its also an opportunity for getting you rank improved. But be prepared that in January things will get back to normal.
$20 is the highest so far in a day(yesterday) for me for 16K Downloads.
there are 1.5K downloads daily these days.
Are there chances i may get > $150 from single app in coming days if this download and revenue ratio is existed or this is mere X’mas effect?