The waist measurment of solution in a normally distributed t

The waist measurment of solution in a normally distributed the standard is known to be the fine inches it is a founded 40% of the students waisted sizes lass than 28 inches what is the waist of students 29.3 30.8 30.2 26.3 26.5

for standard normal table, P( z < -0.253) =0.4

(28-mean)/5 = -0.253