Analysis of a commercial chewing gum gave results of 0.295 mg/g of BHA. To evaluate the accuracy of their results, they performed 5 spike recoveries, adding an amount of BHA equivalent to 0.181 mg/g to each sample. The experimentally determined concentrations of BHA in these sample were reported as 0.377, 0.342, 0.393, 0.345 and 0.327 mg/g.
Calculate the average % recovery for these samples.