I don't even need to look at the data to say that in the US most successful companies have at least one white, male founder. Does that mean that if you start a tech company and are non-white or non-male you should make sure to partner up with one to ensure success? Is it just a bias due to demographics? It it a real factor related to an intrinsic advantage of white males in making successful startups (even if it's just an external cultural factor)?
Or, is it a much more complex issue that can't and shouldn't be so easily infographed and turned into a convenient piece of folk wisdom?
Taking this data, which incidentally is extremely incomplete, and using it as a rubric on how to start your company is little more than cargo cultism.
Also, the amount of founders could be neutral to the success, in such case neither is countering their own success, and again just a matter of samples.
Correlation is not...
What is really necessary is a statistically significant sampling of startups from their inception and tracking the percentage of success and failure depending on various factors. There is simply not enough data in the study at hand to say that 1-person startups are less likely to succeed than 2-person startups, in fact it's quite possible that they are more likely to succeed, we just don't know.
Let's look at this from a different perspective. Assume that the data conclusively shows that 2-founder startups have a higher chance of success than 1-founder startups, by a huge margin (say 10x). Does that mean that you should seek a co-founder before launching your startup? Even then, it does not. Consider two different startup ideas, one is founded on a very solid plan with a good chance of success, the other is founded on a bad plan with a lot more risk. The good plan is going to have a much easier time of finding a co-founder, because the potential co-founder will look at the idea and see that it has a lot of merit and potential and they'll be enthusiastic about joining in, whereas the bad idea will have a much harder time finding co-founders. However, imagine if someone with a bad startup idea pushes much, much harder to get a co-founder because they have learned that startups with co-founders are more likely to be successful. Will that help the company's prospects any or will it just warp the equation and result in a bad company failing even with a co-founder?
I think it's more important to go about a startup with your head screwed on straight than to attempt to imitate the forms of previous success. If you find someone you trust who seems to be a valuable addition to your startup as a co-founder, then by all means make that partnership. But if you can't find a co-founder for whatever reason but you are still quite convinced of your business plan then I don't think you should wait. You should certainly be careful that you aren't deluding yourself and be sensitive to any criticism of your startup idea nonetheless, but a good plan is a good plan even if you go it alone.
I feel This statement assigns specific attributes to the data-points in question where as the original data is more generalized (and suited to the argument). Doesn't the assignment of random attributes skew the point being made and just try to forcibly fit a separate tangential argument?
Your next two sentences explain why this isn't true.