The accompanying data set contains two predictor variables, average annual number of sunny days (days) and average annual precipitation (precipitation), and one numeric target variable, average annual crop yield in bushels per acre (yield). An agricultural researcher wants to create a decision tree for predicting the annual crop yield in bushels per acre for various areas. 

a. List the possible split values for days in ascending order. 

b. List the possible split values for precipitation in ascending order.