Inside Report (3)

Mirror, mirror, on the wall, who gets the fattest paychecks of all?

If you got ''US industrial workers,'' for an answer, you'd better buy a new mirror. A recent survey by a New York management consultant firm assigned US average hourly industrial wages an index of 100, then took similar earnings in other countries in October 1980 and adjusted them by exchange rates at that time. Sweden's wages rated 108, West Germany's 103, Australia's and Switzerland's 102. Canada and the Netherlands trail the US slightly, with ratings of 98 and 97.

US labor and business officials call the statistics ''interesting'' but say buying power is a better measure of relative earnings. The US still leads by this measurement.m