What is the test for jury instruction in the entrapment defense?

"The question of entrapment is generally one for the jury, rather than for the court." Matthews v. United States, 485 U.S. 58, 63 (1988) (citation omitted). "[A] valid entrapment defense has two related elements: government inducement of the crime, and lack of predisposition on the part of the defendant to engage in the criminal conduct." Matthews, 485 U.S. at 63 (citations omitted); see also United States v. Smith, No. 89-30309, slip op. at 841, 858 (9th Cir. January 24, 1991) (no entrapment jury instruction required where defendant fails to produce evidence of both inducement and lack of predisposition). Predisposition is the primary element considered in the defense of entrapment. Id. ¹ "[C]redibility determinations ... are matters left to the trier of fact." United States v. Vasquez, 858 F.2d 1387, 1391 (9th Cir.1988) (citation omitted).