It's worse than that - the probability is biased as you say if the sample were chosen randomly, but they did not claim that. Given that the only distinguishing

It's worse than that - the probability is biased as you say if the sample were chosen randomly, but they did not claim that. Given that the only distinguishing characteristic mentioned is a boolean (engineer or lawyer), and that they only chose one sample, the probability might just as well be 50% - the probability of the person picking the sample deciding one way or the other.