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"In the article, The effect of advancing age on total joint replacement outcomes. mental functional scores are measured by survey and calculated as a quantitative score. Higher scores indicated better mental functioning.

The average preoperative mental functional score for subjects under 50 years of age is 46.9 and the standard deviation is 13.7

Assuming the data are normally distributed, what percent of subjects under 50 years of age have mental functional scores between 19.5 and 74.3?"