In my opinion, this test is flawed to produce INTJ results. Choosing the ideal attributes for the questions (whether or not people actually have them or not, they are the ones that an intelligent human being would desire) will produce an INTJ type.
The E is less desirable than the I. E's depend on others for self-worth and satisfaction. Being dependent is a non-desirable.
The S is less desirable than the N. Human beings use their minds to interpret information. Animals rely on their senses to produce automatic reactions. Animals do not crunch data to figure things out. The S is therefore lower level and basic while the N is higher level and more evolved.
The F is less desirable than the T. Again, the mind is what differentiates a human from an animal. To act based on a rational and well-though-out platform is more logical and more human than to act based on whimsical and often irrational emotions. Someone who acts based on feelings rather than higher-order though processes surrenders the rational for the irrational.
The P is less desirable than the J. This type describes how you interact with the world in which you live. A P trusts everything he or she senses. The P type is not concerned with critical decision making - just processing data to formulate an automatic response. The J type thinks about the data that is received, correlates with other known truths and values, and then rationalizes the best decision, which may or may not be different from the automatic response, but certainly represents the better response.
The ESFP represents the lowest level of evolution, it is the most animal-like and the most corporal (Keirsey calls this type the "performer").
The INTJ represents the highest level of evolution, it is the most human-like and the most cerebral (Keirsey calls this type the "mastermind").
Would you rather be a performer, like a dog begging for attention by doing tricks, or would you rather be a mastermind, who is 100% self-confident and controls every aspect of his own destiny?
Most semi-intelligent humans will recognize the attributes of the INTJ to be the most desirable and will therefore choose them, whether or not they accurately represent themselves. It is therefore no surprise, that on a board of pre-meds, the INTJ type is overwhelmingly self-selected.
The test is totally bogus in my opinion. For what it's worth, I came out INTJ first, but then when I went back and really thought about what I was and made some concessions that I was not perfect, I scored INFP. I would guess that there really are only 1% INTJs (supposedly the rarest personality type), but way, way more than that self-select that type inaccurately.