=+69. Let x denote the maximum physical stress that a unit of a certain product encounters during its lifetime. Suppose that x is normally distributed with 99th percentile 5 5.33 and 10th percentile 5 1.72

(suggested in the article “A Formulation of Product Reliability through Environmental Stress Testing and Screening,” J. of the Institute of Envir. Sciences, 1994: 50–56; the unit for x was unspecified). What proportion of these units have maximum stress values exceeding 5? What proportion have maximum stress values less than 2?