The sample space is

S = {Low, Middle, High}.

The experimental proability of each event is given by the relative frequency of the outcome. Here is the table once again together with the outcome for each:

Week	1	2	3	4	5	6	7	8	9	10
Dow	3,210	3,200	3,270	3,220	3,220	3,250	3,280	3,270	3,220	3,240
Outcome	L	L	H	M	M	M	H	H	M	M

Since H occurs in three out of ten trials, its probability is 3/10 = 0.3. Similarly, M, which occurs 5 times in 10 trials, has a probability of 0.5. That leaves L with the probability of 0.2 (since the probabilities of the events must add to 1). Thus, Choice A is the correct answer.