Total world rice production (million tonnes)
First discuss the assumption of independence and the possibility of serial correlation of the errors.
The Durbin-Watson statistic is:
High serial correlation ==> d close to zero.
Is d = 1.291 indicative of serial correlation?
Select Random Normal Data. Click Accumulate, then click Simulate about 100 times to build up the sampling distribution of d.
A value as low as 1.291 is very unlikely for data from a normal linear model.
Strong evidence that years with unusually high (or low) yield tend to follow each other.
Warning
An unusually small Durbin-Watson statistic can be caused by either serial correlation or nonlinearity.
The time series gives the total world rice production (million tonnes) between 1961 and 2001.