A person's character, or propensity, is inadmissible to show that person's conduct on a specific occasion.

United States v. Balthazard, 360 F.3d 309, 313 (1st Cir. 2004) ("When the relevancy of evidence is conditioned on the establishment of a fact-in this case, that the other marijuana growing operations were undertaken in furtherance of the charged conspiracy-the offering party need only introduce...Evidence of a condition upon which the relevance of evidence depends is sufficient if a reasonable trier (such as a jury) can find by a preponderance of the evidence that the condition exists.

Fed. R. Evid. 602 advisory committee's note ("It will be observed that the rule [requiring personal knowledge] is in fact a specialized application of the provisions of Rule 104(b) on conditional relevancy.").A person has the personal knowledge that a witness must have if and only if the evidence is sufficient to permit a reasonable trier of fact to conclude that the witness personally perceived the matter. The preliminary question of personal knowledge is governed by the standard of whether the evidence is sufficient to allow a reasonable person to conclude that the person has personal knowledge; the applicable standard is not the more demanding preponderance of the evidence standard.

Fed. R. Evid. 801(a)(2) ("A 'statement' is ... (2) nonverbal conduct of a person, if it is intended by the person as an assertion.").Nonverbal conduct can be a "statement" for purposes of the federal prohibition against hearsay and, thus, nonverbal conduct can be "hearsay."