To solve this, we need to use the z statistic. The formula for z score is:
z = (x – u) / s
where x is sample value = less than 90, u is the sample mean = 90.6, s is the standard deviation = 17.2
z = (90 – 90.6) / 17.2
z = -0.035
From the standard distribution tables:
P (z = -0.035) = 0.4860
Therefore there is about 48.60 % chance that it will be less than 90 pounds