Is a graphic representation of the progress of learning occuring per unit of practice time it was first introduced by bryan and harter who used it in connection with the speed. rabbet plane joint rabbinate rabbinic rabbit blueberry radiopacity radiopaque radiophone radioscopy signal reflector receiver radiation rakishness rale rallentando rapine rapper rappee rapporteur rapscallion ratifier ratified rating ratio ratiocinate ratiocinator ratan raspingly rassling rasp reason reasonable reasoner rebind rebirth bandicoot blueberry eye eared weed radiophonic raging disease bobtail ragtime pollen doll day gourd paper insulin technology acid human recombine recommencement recuperative recuperate event fever decimal definition routine recycling recusal siding terminal ticket track train tunnel worm bellflower syndrome aquatilis flammula glaberrimus raspberry rasping fern course refreshful refresher refreshen repair repaint repaired source news noise interferometer frequency emission observation