Hi guys, how to do this in a php file

Showing ads only to 20% percent of visitors. Or showing different ads to another 80% visitors

any way that can work, maybe using time intervals, like the visitors that visit the site at minute 0-12 only that show it, and visitors that visit the site at minute 13-59 is not. Or another methode

please help or share if you have, this should be easy enough and many people should need it, already googling it but still cant found it

I believe you can control the percentage of users that see what content in Google Analytics. Try clicking the Adwords/Adsense tab in GA and see what comes up. I don't have ads on any of my websites, so I can't really say this for sure, but I've definitely seen this type of thing before.

Generate a random number in the range of 1 -100, if it is greater than 20 show the 80% set otherwise show the 20% set.

Originally Posted by chrishirst

Generate a random number in the range of 1 -100, if it is greater than 20 show the 80% set otherwise show the 20% set.

But...but..but that's so much SIMPLER!

To be able to use any math here you'll need to know in advance how many visitors you'll get in a day

How is that possible?

Originally Posted by miki86

To be able to use any math here you'll need to know in advance how many visitors you'll get in a day

How is that possible?

If you wanted to be very specific, then you would need to know the exact number of visitors you'll get that day. In other words, you'd need to create a psychic script, which obviously isn't possible. Chrishirst's solution would work like this:

$number = rand(1,100);

$_SESSION['showads] = $number;
//Then on every page load:
if($_SESSION['showads']>20){
//Show 80% ads
}
else ...

I think he meant showing ads to 20% of visitors, not 20% chance of showing ads

btw it shoud start with 1 not 0...rand(1,100)

Originally Posted by miki86

I think he meant showing ads to 20% of visitors, not 20% chance of showing ads

I know, but that's the only way to do it dynamically, without programming in an average number to calculate from.

Originally Posted by miki86

btw it shoud start with 1 not 0...rand(1,100)

Woops, yeah. Fixed!

I did a much more complicated set of rules using javascript and a cookie (site was mainly flat pages) - it's easy enough.

Originally Posted by miki86

I think he meant showing ads to 20% of visitors, not 20% chance of showing ads

Sure:

But! As said previously, calculating an average of a unknown value is impossible, so we have to work with probability

There is:

A 1/100 probability of any particular number being the result.
A 80/100 probability of the number being >20 20)
A 20/100 probability of the number being < 20 <<< actually this should be 21 to include the value of 20

AND
QUOTE=miki86;1215720]I think he meant showing ads to 20% of visitors, not 20% chance of showing ads [/QUOTE]

My psuedo formula does say to show different sets of adverts NOT "do not display adverts" to one of the groups.

Although, in actual fact, the less than condition should be 21 to include the value of 20 as well.

I agree probability is the only way to do it.
It wont be equal to 20:80 because without right values it can't be calculated to be precise but given the circumstances that won't be crucial, ads will be shown.

All things being equal, using probability will only need to be a start point, simply because the same script can start a "hit/shown" counting process and compare "real" counts against the probability results.