Answer:
0.25239
Step-by-step explanation:
We start by calculating the z-score
Mathematically;
z-score = (x-mean)/SD
Z-score = (19.5-20.5)/1.5
z-score = -0.667
The probability we want to calculate is;
P( x < -0.667)
we can use the standard normal distribution table to get this
That would be;
0.25239
P( x < -0.667) = 0.25239