What is the equation in point-slope form for a perpendicular bisector of a segment with endpoints R (-3,2) and S (9,-2)?

The given dot plot represents the average daily temperatures, in degrees fahrenheit, recorded in a town during the first 15 days of september. if the dot plot is converted to a box plot, the first quartile would be drawn at , ( 59,60,61,62) and the third quartile would be drawn at . (61,62,63,64)