Bounce rate as I understand it is the numbers of visitor who click your site but don’t stay long. The quicker visitors hit the back button and never navigate your other site page. The higher your percentage of your bounce rate.So, the higher the bounce rate percentage the more giving negative signal to google. Likewise, the longer your visitors stay and navigate your site the lower bounce rate percentage. I believe this is one factor that google use in their algorithm when ranking a website because if not. Google shouldn’t include bounce rate and exit rate in google analytic.