The equation of the linear regression line represents the relationship between the amount of time, in minutes, people spend using their cell phone, x, and the number of text messages they send, y. yˆ= 21/5x + 98 what does the slope of the line represent? for every 21 minutes that people spend using their cell phone, the number of texts they send increases by 5. for every 5 minutes that people spend using their cell phone, the number of texts they send decreases by 21. for every 21 minutes that people spend using their cell phone, the number of texts they send decreases by 5. for every 5 minutes that people spend using their cell phone, the number of texts they send increases by 21.