{c} If you wanted to distinguish the top 20% of ARI scores from the bottom 80%, what would be the score that could be used as the cut-off? Show your work and write your answer in the box. [11A drug policy researcher wants to identify the degree to which a group offormer drug addicts in a population are at risk for becoming addicted to drugs again in the future. Based on various risk factors, the researcher develops a measure of risk {called the Addiction Risk Index, or ARI]. High scores ofARI indicate a higher risk of future drug addiction than do low scores. Assume that ARI scores are normally.I distributed with mean 50 and standard deviation 4