The correct answer is that they 'are not valid'. If the experiment is biased, it entails that it is not objective. For a experiment, and its results, to be valid, it had to be carried out objectively and taking into account all factors.
It is possible that the results disprove a hypothesis, but to be certain it is necessary to see which was the original objective of the study, as it might also prove to some extent a hypothesis, which is probably also biased.
The answer is:
The children were lying warmly and tightly in bed, while they were having sweet dreams; and momma in her bandana, and I in my cap, had just got ready to take a long winter's nap.
An informal register is used when speaking or writing to people we know well, like family and friends. There are no considerable rules in informal language, so it is appropriate to tell jokes and the use of slang, contractions, personal opinions, incomplete sentences and extra punctuation.
