Expert witness: Ten times, and

Answer choices

1. A

   Too Weak3% picked this

   If similar results had been found after 100 test drops of the defendant’s blood, the evidence

   This answer informs us that the evidence is not currently 100% maximally strong, since there's room for it to be stronger. But the fact that something could be stronger does not make it weaker. If I brew some strong coffee, and then my wife asks, "Wow. What could weaken the strength of this coffee?", it doesn't count to say "Hey, I could've made it even stronger!"

   3%
2. B

   Too Weak: sometimes11% picked this

   Expert witnesses have sometimes been known to fudge their data to accord with

   This answer creates a possibility that this expert witness might be among those that fudge their data. (Fudging data = stretching it / fabricating it so that it says what you want it to say) Is this data fudged? Maybe, maybe not. The strength of this answer is sometimes, so it's only telling us that there was "at least one expert witness who once fudged her data". That creates a sliver of doubt about this witness, but no more than that.

   11%
3. C

   Correct64% picked this

   In an eleventh test drop of the defendant’s blood, the area stained was also less than 9.5 cm2—this

   Why this is right

   #1 this highlights the potential variability of this blood dropping test and makes us think that the current ten-drop evidence was insufficient to give us a clear picture. The ten times they previously dropped blood were all between 4.5 and 4.8, and so the witness is saying, "It looks like the witness's blood is always gonna be in that range". The fact that the eleventh drop was 9.3, twice as large as the other ten trials, shows that there is a lot of variability, and so to know the range of possibility we need to do more than ten drops. #2 this actually hurts the conclusion. The conclusion is saying "a single drop stains much less than 9.5", but 9.3 is not much less than 9.5; it's only a tiny, tiny bit less.

   Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

   64%
4. D

   Strengthens, if anything19% picked this

   Another person’s blood was substituted, and in otherwise identical circumstances, stained between 9.8 and 10.6

   This answer shows that it was theoretically possible to stain above 9.5 in this testing environment. If the testing environment wasn't preventing 9.5 from happening, then we'd have to assume it's the nature of the defendant's blood that was doing so. Perhaps the defendant's blood is viscous and doesn't spread as much, whereas this other person is on blood thinners and so stains a much wider area. We can't use this answer to say, "You see? Your test was messed up", because it seems to prove the opposite. The test isn't the problem; another person's blood was able to stain something resembling 9.5 cm.

   19%
5. E

   Too Weak: not all3% picked this

   Not all expert witnesses are the authorities in their fields that they

   This answer creates a possibility that an expert witness might not really be an authority in the field of blood dropping. Does that mean that this witness isn't an authority? Maybe, maybe not. The strength of this answer is not all, so it's only telling us that there is "at least one expert witness who is not an authority in their field." That creates a sliver of doubt about this witness, but no more than that.

   3%