Sign this “expert” up for the defense, immediately.
Prosecution must prove its case “beyond a reasonable doubt”. If there is a 48% chance it was Zimmerman screaming there is huge doubt.
By the time you factor in margin of error, saying there’s a 48% chance that it was GZ is statistically the same thing as saying there’s a 1 in 2 chance that it was GZ and a 1 in 2 chance that it was TM.
You could get the same result by drawing straws. Which would be just as admissible in court as this would.