Using x = 85 (for 850,000 registered boats), what is the single value that is the best predicted number of manatee fatalities resulting from encounters with boats?

Refer to the display obtained by using the paired data consisting of Florida registered boats (tens of thousands) and numbers of manatee deaths from encounters with boats in Florida for different recent years (from Data Set 10 in Appendix B). Along with the paired boat , manatee sample data, Stat-Crunch was also given the value of 85 (tens of thousands) boats to be used for predicting manatee fatalities.

Data Set 10: Manatee Deaths 

Annual Florida data for 24 years are provided (first five rows shown here). DEATHS is the annual number of Manatee deaths caused by boats, BOATS is the number of registered pleasure boats (tens of thousands), POP is the Florida population (millions), and WATER TEMP is the annual mean water temperature (°F).