Mizuho Financial Group Inc. will tie up with Google LLC to utilize the American tech giant’s know-how to analyze clients’ transaction data to improve the quality of customer service, a source familiar with the matter said Tuesday. Mizuho also hopes to boost digitalization through personnel exchanges with Google, as the Japanese group has lagged in the field because of the need to deal with repeated system failures experienced at its key banking unit, the source said. Through the cooperation deal, expected to be announced soon, Mizuho plans to send its employees to Google to gain practical know…