Another researcher reads the study regarding cleanliness and morality and is very skeptical. She recreates the original experiment and runs it on her own sample. She does not get the same results; in fact, her results suggest that cleanliness has no effect on morality.. Which of the following conclusions is BEST? There is clearly no way to know about the effect of smell on behavior. Because the original study did not replicate, this means the original results are certainly false. Because the original study did not replicate, this suggests there may be issues with the original study's validity. The original researcher must have made up their data and should be investigated for fraud. Because the original study did not replicate, this means the second researcher's results are certainly false.

1. There is nothing related to smell in either of the two studies. So this has to be false.

2. Failure to replicate does not necessarily mean that the original results are false. Maybe the replication results are false. Or maybe there are issues with validity.

3. This seems most appropriate. An example of a validity issue is that the sample in the original study was not diverse enough. Let's say that the original author only recruited American participants. Then, the results of the original study might not hold true for Chinese participants.

4. Again, see (2).

5. This is the opposite of (2). Failure to replicate does not necessarily mean that the replication results are false. Maybe the original results are false. Or maybe there are issues with validity.