(see all hypotheses here)
(see category descriptions here)
(see all results here)
Here are some relevant results:
222-221 .0003
222-122 .1945
222-022 .0227
222-220 2E-6
221-220 2E-06
122-022 .0166
211-221 .2543
121-221 2E-12
122-121 .0001
122-112 .2232
122-120 .0002
122-012 NR
221-021 .0003
221-210 .3332
022-012 .7436
022-021 .0006
220-210 NR
220-120 .0514
The first thing to notice here is the behavior of the category 222. It is significantly related to the categories 221, and 220. This indicates that the author of the triple agreements was not Luke.
If Luke is the editor, than we would expect category 220, which consists of Matthew/Mark tradition ignored by Luke, to be related to 221, Matthew/Mark tradition selected against by Luke, and 222, Matthew/Mark tradition selected for by Luke, more than 221 and 222 are related to each other. This is exactly the pattern we see. We see the same pattern of relations between 222, 122, and 022, although the relationships are not significant here.
Next we can observe that 221 is significantly related to the Markian categories 121 and 021, and not related significantly to the Matthian categories 211, and 210. This indicates that agreements between Mark and Matthew were originally authored by Mark, and subsequently copied and edited by Matthew. We can also observe that category 122 is significantly related to the Markian categories 121 and 120, and not significantly related to the Lukian categories 012 and 112. This indicates that agreements between Mark and Luke were originally authored by Mark, and subsequently copied and edited by Luke.
More confirmation of this can be found by looking at the way 220 relates to 210 and 120, and by looking at the way 022 relates to 012 and 021. While these relationships are not significant, they also suggest Mark as the original author.
All of this taken together provides strong evidence that when Mark agrees with one or both of the other 2 synoptic gospels, Mark is the original author of the text.