title: ARIMA checking and validation in R
body: <p>I want to validate and check the ARIMA model from my data wihch results to be (0,1,1)x(0,1,1)_12.
  <img src="https://i.stack.imgur.com/n88LG.png" alt="enter image description here"></p>
  
  <p>I want to determine the parameters of such model with R and after make a cross prediction. 
  I have applied:</p>
  
  <pre><code>parameters  &lt;- arima(x1_1_12, c(0, 1, 1),
                 seasonal = list(order = c(0, 1, 1), period = 12)))
  Coefficients:
        ma1     sma1
    -0.4018  -0.5569
  s.e.   0.0896   0.0731
  
  sigma^2 estimated as 0.0002543:  log likelihood = 353.96,  aic = -701.92
  </code></pre>
  
  <p>I want to obtain the p-values and estimate the model parameters and finally check the model.
  Thanks! </p>