To find the probability we need to use the z score formula, given by:
[tex]z=\frac{x-\mu}{\sigma}[/tex]where x is the value we like, mu is the median and sigma is the standard deviation.
Then the z score is:
[tex]z=\frac{20-20}{2.6}=0[/tex]Then we have to look for the proability:
[tex]P(z>0)=0.5[/tex]Therefore the probability that a given infant is longer than 20 inches is 0.5 or 50%.
