Final answer:
The probability of selecting an even number (event E) from the sample space S = {1, 2, 3, 4} is 0.5, as there are two even numbers and four total numbers in the sample space.
Step-by-step explanation:
The question asks to compute the probability of the event E="an even number" given the sample space S = {1, 2, 3, 4}, where all outcomes are equally likely. In this sample space, there are two even numbers: 2 and 4. To calculate the probability of event E, we take the number of favorable outcomes (which are the even numbers) and divide by the total number of outcomes in the sample space.
The sample space S is {1, 2, 3, 4}. Let event A be the even numbers (A = {2, 4}) and the probability of event A occurring is P(A) = number of favorable outcomes (even numbers) / total number of outcomes (sample space). With two even numbers in the sample space, the probability is P(A) = 2 / 4 = 0.5.
Thus, the correct answer is A. 0.5, representing that the event of choosing an even number has a probability of 0.5 or 50%.