From Figure 1, it can be observed that the yields of off-season longan are random, from 400 kg/rai to 6000 kg/rai. Thereafter, all the collected data are tested to confirm, using the following tests: (1) goodness-of-fit test, (2) normal distribution test, (3) linearity test, (4) homogeneity of variance test, and (5) multicollinearity test. The results of these tests are presented in Table 4 and Figure 2.