title: ezANOVA R check error normally distributed
body: <p>I am using ezANOVA to implement the analysis of an experimental design having a within subject variable and a between subject variable. I successfully implemented ezANOVA as follows: </p>
  
  <pre><code>structure(list(Sub = structure(c(3L, 3L, 3L, 4L, 4L, 4L, 1L, 
  1L, 1L, 2L, 2L, 2L), .Label = c("A7011", "A7022", "B13", "B14"
  ), class = "factor"), Depvariable = c(0.375, 0.066667, 0.15, 
  0.275, 0.025, 0.78333, 0.24167, 0.058333, 0.14167, 0.19167, 0.5, 
  0), Group = structure(c(2L, 2L, 2L, 2L, 2L, 2L, 1L, 1L, 1L, 1L, 
  1L, 1L), .Label = c("A", "B"), class = "factor"), WithinFactor = c(0.6, 
  0, -0.3, 0.6, 0, -0.3, 0.6, 0, -0.3, 0.6, 0, -0.3)), .Names = c("Sub", 
  "Depvariable", "Group", "WithinFactor"), row.names = c(NA, 12L
   ), class = "data.frame")
  
  
  mod.ez&lt;-ezANOVA(data,
            dv = .(Depvariable),
            wid = .(Sub),  # subject
            within = .(WithinFactor),  
            between=.(Group),
            type=3, 
            detailed=TRUE,
            return_aov=TRUE)
  </code></pre>
  
  <p>I am stuck with the procedure to check normal distribution of the residuals. 
  I've tried the following:</p>
  
  <pre><code>shapiro.test(as.numeric(residuals(mod.ez$aov)))
  </code></pre>
  
  <p>But I get the following error </p>
  
  <p>Error in shapiro.test(as.numeric(residuals(mod.ez$aov))) : 
    sample size must be between 3 and 5000</p>
  
  <p>If I call <code>residuals(mod.ez$aov)</code> the result is NULL.</p>
  
  <p>I alternatively used lmer where check of the residuals seem straighforward</p>
  
  <pre><code>plot(fitted(model_lmer), residuals(model_lmer))
  </code></pre>
  
  <p>However, as ezANOVA also has implemented sphericity's tests and corrections I would like to stick to it and find a way of check assumption re normality of the residuals.</p>
  
  <p>Any help greatly appreciated</p>