Which of the following is most likely to be a subjective probability?

Subjective probability is a prediction that is based on an individual's personal judgment, not on mathematical calculations.

For option a, the prediction is based on the human resources manager's estimation. Hence, it is a subjective probability.

For option b, c and d, the predictions are based on the calculations on the sample space. Hence, they are not subjective probabilities.

The answer: a. The human resources manager estimated that the probability the applicant would accept the job offer was 0.35.

In option (a) the human resources manager is making a conjecture about the future course of action of the applicant. The manager's basis for that conjecture is not given, but in a typical situation, it would be based on the applicant's responses to questions, the manager's experience with other applicants, and his knowledge of the applicant's history. It also would make use of many behavioral clues. It really is much like a card-playing strategy. Yes, it is subjective.

In both (b) and (c) a sample space is known, and a choice is made from that space. In both cases the choice appears to be random, with a uniform distribution. That would be objective.

Option (d) involves the use of a sample in order the predict the probability of an event in the population. The sample may not be representative, and the measurement may not be even be accurate, but interestingly, that does not even matter. To use a sample to predict the outcome would be a very straightforward calculation. Even if it is not accurate, it certainly is objective.

A