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I have time series data. Not sure whether the series is stationary or not. I applied
adf.test and got a p-value much higher than 0.05 which I think means that the data is not stationary. I took differencing once to check the p-value again. And I see that p-value has gone below 0.05. Can I assume that the data is stationary and ready for forecast? Is there any other way to confirm this in 'R'?