omar has developed an intervention to improve the relationship between parents and their preschool-aged children. to evaluate the effectiveness of his intervention, omar video-records parents interacting with their children and has two research assistants score the level of warmth in each interaction. omar then compares the two sets of scores to examine – reliability. he finds a high positive correlation of – between the two raters’ scores. if the observers were rating a categorical variable, omar could have also looked at the – statistic.