All odd numbers greater than 2 are prime

A physicist, a mathematician, and an engineer are sitting around and one of them says "It says here that Professor X has come up with a new theorem that all odd numbers greater than 2 are prime". Each person present thinks to himself:

* MATHEMATICIAN: 3 is prime, 5 is prime, 7 is prime, 9 is not-prime. Theorem disproved!
* MATHEMATICIAN (alternate): 3 is prime, 5 is prime, 7 is prime, the rest follows by Mathematical induction.
* PHYSICIST: 3 is prime, 5 is prime, 7 is prime, 9 is not-prime - oops, experimental error!
* ENGINEER: 3 is prime, 5 is prime, 7 is prime, 9 is approximately prime, 11 is prime, 13 is prime ...
* MECHANICAL ENGINEER: 3 is prime, 4 is prime, 5 is prime, 6 is prime ...
* COMPUTER ENGINEER: 3 is prime, 3 is prime, 3 is prime, 3 is prime ...