Correlation coefficients are expressed by a number between -1 and 1.
If the value is -1 or 1 it indecates a perfect (negative and positive) correlation.
If the value is 0 indicates null correlation.
As the correlation value for you data set is -0.833 it is very close to the -1. It indicates a good correlation in the data. Then, the value you predicted is reasonably close to the actual value.
