It means that 55.9% of the variations of the sale price, a response variable, are explained by the predictor variables. With this result we can infer that there is a rather weak relationship between predictor variables and response variable. Further, the value of Ra2 = 0.529 which provides a somewhat similar interpretation, with regards to the measurement of the model adequacy. <Note: the sample contains substantially more data points than the number of β parameters in the model. >
Despite their utility, R2 and Ra2 are only sample statistics. Therefore, it is dangerous to judge the global usefulness of the model based solely on these values. A better method is to conduct a test of hypothesis involving all the β parameters (except β0) in a model. From the ANOVA section under the SPSS output, SSR is 133482.6, SSE is 105410.2, MSR is 10267.888 and MSE is 540.565. With this, the F-ratio is 18.995 with a p-value of approximately 0 and SSyy is 238892.8. With the F-test results obtained from the ANOVA table, we conduct the Global F-test with, H0: β1= β2 = β3 = β4 = β5 = β6 = β7 = β8 = β9 = β10 = β11 = β12 = β13 = β14 = β15 =