BUSINESS DIGEST
Toys 'R' Us Colluded On Prices, Judge Rules Toys ''R'' Us, the biggest retailer in the nation's cutthroat toy business, violated Federal trade laws by colluding with manufacturers, including Mattel and Hasbro, to keep prices for toys like Barbie and Mr. Potato Head artificially high, a judge ruled. Upholding F.T.C. charges, the judge, James P. Timony, agreed that Toys ''R'' Us used its market muscle against its emerging chief competition, warehouse clubs like Price/Costco, BJ's and Sam's Club. Toys ''R'' Us said it would appeal the ruling. [Page A1.]