The first thing you learn about statistics is that you can do all the analysis in the world, but if your basic data is flawed then all of your conclusions are u

The first thing you learn about statistics is that you can do all the analysis in the world, but if your basic data is flawed then all of your conclusions are useless. You state this 3/4 number like it is a hard fact, however it is a very biased sampling. It involves YOU, who obviously has a problem with your laptop or wouldn't be writing this article. So, clearly the probability your laptop is damaged is 1. Then you add in 3 friends, who you probably chose because 2 of them have problems. Let me put it this way. I have a Macbook that isn't broken, and know 3 other people who all bought Macbooks about the same time as me and none of us have had problems. Just like your scenario, there is no reasonable conclusion I can make from that. However, if I was to ask for the first 4 people who own a mac to respond if it is currently working or not, that would be a (decently) random way of collecting data. Finally let's throw in user problems. Just because you have friends that have visited the Apple store does not mean that their device is a failure. Factor in user problems like disabling wireless accidentally and being unaware how to start it, and user's fault like dropping your laptop or pouring water on it. All events your friends could have a reason to lie to you about the real reason for their visit.