SAN FRANCISCO — The California Supreme Court tossed a $15 million overtime award to bank employees Thursday because of a faulty statistical sample, but justices were careful not to toss at-large reliance on statistics in wage-and-hour class actions.

Business interests had hoped the court would use Duran v. U.S. Bank National Association to limit plaintiffs attorneys’ use of statistical samples to generalize damages and liability over an entire class. Plaintiffs employment attorneys worried such limits could destroy their cases.