Question

The masses of students follow a normal distribution with a mean m and a standard deviation of 1.2 kg. If 90% of the students have a mass of less than A kg, find the mean m.

Answer 1

Standard deviation,  = 1.2

Probability = 0.9 for mass of less than A kg

Using inverse normal distribution table, z = 1.282

z = (x – $\mu$ )/ $\sigma$

1.282 = (A – m)/1.2

A – m = 1.5384

m = 1.5384 – A