The lengths of sweet-pea flower stems are normally distributed with mean 18.2 cm and standard deviation 2.3 cm
a. Find the probability that the length of a flower stem in between 16cm and 20cm.
b. 12% of the flower stems are longer than h cm. 20% of the flower stems are shorter than k cm. Find h and k.
C. Stem length less than 14 cm are unacceptable at a florist's shop. In a batch of 500 sweet peas estimate how many would be unacceptable.