During a nirmal economy with a $74\%$ of orobability the common stick of d&f oil is excoetcfed to teturn $13\mathrm{.}2\%.$ During w recsions with a $15\%$ probability the return stick is $6\mathrm{.}7\%$ during a coom with $11\%$ probbailith the stock teturn is $24\mathrm{.}5\%$ what is the standard deviation on these returns