What is the test for good cause in a motion for a new trial based on juror misconduct?

Good cause, in the context of a petition for disclosure to support a motion for a new trial based on juror misconduct, requires "a sufficient showing to support a reasonable belief that jury misconduct occurred...." ( People v. Rhodes (1989) 212 Cal.App.3d 541, 552, 261 Cal.Rptr. 1 ; accord, People v. Wilson (1996) 43 Cal.App.4th 839, 850852, 50 Cal.Rptr.2d 883.) Good cause does not exist where the allegations of jury misconduct are speculative,

[154 Cal.Rptr.3d 313]