MTTR Caliculation

hi , i am new to eazyBI . i want to calculate MTTR with as following . here is my use case

MTTR is defined as: MTTR = ((13-wk average backlog) / (13-wk average fixed rate) x 7)

backlog is just outstanding defects at a given point in time , lets say on Sunday midnight every week. fixed rate is defects transitioning to terminal state (C,J,D,U,V) in the course of a week , lets say week beginning Sunday minight