To find the probability, we need to consider the number of favorable outcomes (getting the sequence 4, 3, 2, 1) and the total number of possible outcomes when rolling a fair 6-sided die four times. Since each roll is independent, the probability for each roll is 1/6.
The probability of rolling a 4 on the first roll is 1/6, for rolling a 3 on the second roll is 1/6, for rolling a 2 on the third roll is 1/6, and for rolling a 1 on the fourth roll is 1/6.
To find the probability of all four rolls occurring in a specific sequence, we multiply the probabilities together:
(1/6) * (1/6) * (1/6) * (1/6) = 1/1296.
Therefore, the probability of getting the sequence 4, 3, 2, 1 when rolling a fair 6-sided die four times is 1/1296, which is approximately 0.0008 when rounded to four decimal places.