Originally Posted by

**ptgatsby**
Well, the way I see it, the rough way of seeing the numbers would be (I make no statement to the accuracy of this, I'm just typing it out as I think of it).

total people in family tree = 1st gen + 2nd gen + 3rd gen (...)

Where 1st gen = 1, x gen = 2.3^x

With (1st to last-1) * 2.

With probability being 3% of the population being INTJ, with 0.97^(number of people in tree) not knowing of an INTJ.

Probability of knowing an INTJ in your family;

1st gen = 2 = 6%

2nd gen = 2+2.3 = 4.3 = 12%

3rd gen = 2+2.3*2+2.3^2 = 11.89 = 30%

4th gen = 2+2.3*2+2.3^2*2+2.3^3= 29.347 = 59%

Since I didn't build this in excel for quick calcs, I won't work out adding a circle of friends, work and so forth. I did look up birth statistics and we are actually below 2.3, although with the timeframe we are talking about, it's probably fairly safe - it has gone up and down over 40-80 years! And of course, if you are seeing anyone, it is far more likely to know someone as a result of the two families... Anyone who goes to university has a much higher chance of knowing an INTJ as well... and if you are younger...

I'd give myself a 95% chance odd (well, higher, but around there) of not knowing an INTJ with a headcount of my family, friends and department at work - I know two, so nothing errant there. Taking on an extra 4-5 friends, maybe a couple of their SOs, maybe a few people at work - well, I'd say the majority of the population will know an INTJ (or be one themselves).