Focus on the pronunciation of test group
English definition of “test group”
noun [C] MARKETING
› a group of people who try a product or service to see how well it works, and whether they like it or would buy or use it: We always play the scripts for our ads to test groups of viewers before we finalize them. → Compare control group
› a group of products that are tested and compared to each other: Every inkjet printer in our test group printed sharp text.