How do I know if people can tell if I am online on Facebook on my computer and mobile device.?

[NoahUSA]

I use Facebook quite a lot on my mobile device (Gallaxy S3). I have people who use this against me because if I don't answer text messages right away they then throw it in my face that they know I'm on facebook and why aren't I texting them right back. So on the computer I turned off chat, and on the phone I turned off chat. I then used my sisters phone, created a fake Facebook name, friend requested it and checked to see if I was shown as online. I couldn't find myself on chat. However, how do I know this is the true way to eliminate people from viewing my online status? Am I in the safe? Did I successfully do it? The thing that concerns me is that I can see other people who are on line. I can see either a green dot next to a person's name or I can see a phone symbol and a number after the phone like 23m or 1d. What does that mean? Does that mean that the person hasn't logged in for 32 minutes or has been on for 32 minutes. I think that Mark Z has gone way to far with this privacy stuff letting everyone see everything. You can also see what a person has edited. Any help would be greatly appreciated.

[Sharon K]

I would like to know what 1m ....25m .... 1 d ...means....I want to understand because I have been told these things have been behind my name...on Facebook chat.
Is there anywhere I can go to read up on everything I want to know to understand how I can use Facebook best and know what something like this means when people tell me things.

[Kittysue]

That 23m means the last time they checked their account was 23 minutes ago. 1d means one day