Final answer:
In a probability model, the probabilities of an outcome are numbers between 0 and 1. 1/2, 3/4, 2/3, and 0 could be valid probabilities, while 1.5 and -1/4 are not.
Step-by-step explanation:
In a probability model, the probability of an outcome is a number between 0 and 1 (inclusive). Therefore, the numbers 1/2, 3/4, 2/3, and 0 could be the probabilities of an outcome. However, 1.5 and -1/4 are not valid probabilities because they are outside the range of 0 to 1.