A dataset on pregnancy rates among girls in 13 north central Florida counties has information on the total in 2005 for each county i on T i = number of births and y i = number of those for which...

A dataset on pregnancy rates among girls in 13 north central Florida counties has information on the total in 2005 for each county i on T_i
= number of births and y_i
= number of those for which mother’s age was under 18. Let πi be the probability that a pregnancy in county i is to a mother of age under 18. The