Stats are nice, but usually, hardly tells anything about real-life. Simply because people often answer things that don't necessarily correlates with their real-life intentions, and contradictions can often be found applenty in those.
For example, if you ask people about if they think the average worker in your country work enough for his pay, there will be like, 50% of people saying no. But if you ask everyone if they think THEY work enough, 100% will say yes. It all depends on HOW you ask a question, who, when, why, wordings, size of sample population, etc, etc... There are too many factors to consider, and even if you narrow this down effectively, you can still make stats say what you want to say.
The only thing a survey shows, is what people answered to that survey and nothing else. This can't be seen as reflective of their actions in real-life, as you can't prove those people will really answer honestly, as you don't know if they won't change ideas, in other words, the future can't be predicted.
This survey about buying intentions for game systems is flawed. First, what about people considering to buy more than one? This sure has to be taken into consideration, as I'm sure some people will buy more than one. Maybe the Wii first, but they could also buy another one afterwards, no? And how can we be sure that those who answered will really proceed with their purchase and won't change ideas down the line? And what about people who will buy more than one unit because it will break in 2 years, or more than one because they bought one for the kids too, or god know what else?
This survey is interesting, but shouldn't be taken seriously. Especially since it's just a small bunch of people. It can't be reflective of a larger population sample.
I suggest you read an article I wrote about statistics and numbers at my website :
http://www.realnoize.net/html/articles_6.html
Sure, it's not about gaming, but more about statistic usage, but still, I think it explains a few things about stats we should all be aware of.
In other words, it's about developping an habit of criticizing and questionning whatever has been put in front of us.