Running examples in ‘mnreadR-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: mnreadCurve
> ### Title: MNREAD curve plotting.
> ### Aliases: mnreadCurve
> 
> ### ** Examples
> 
> # inspect the structure of the dataframe
> head(data_low_vision, 10)
   subject polarity treatment vd  ps    rt err
1       s1  regular         A 20 1.3  6.66   0
2       s1  regular         A 20 1.2  6.53   0
3       s1  regular         A 20 1.1  7.46   0
4       s1  regular         A 20 1.0 11.69   0
5       s1  regular         A 20 0.9 11.16   0
6       s1  regular         A 20 0.8 12.75   0
7       s1  regular         A 20 0.7 23.09   0
8       s1  regular         A 20 0.6 34.62   1
9       s1  regular         A 20 0.5    NA  10
10      s1  regular         A 20 0.4    NA  NA
> 
> #------
> 
> # restrict dataset to one MNREAD test only (subject s1, regular polarity)
> data_s1_reg <- data_low_vision %>%
+    filter (subject == "s1", polarity == "regular")
> 
> # plot the MNREAD curve 
> ## Not run:  mnreadCurve(data_s1_reg, ps, vd, rt, err)  
> 
> #------
> 
> # restrict dataset to one subject (s1) and plot the MNREAD curves using ONE GROUPING ARGUMENT 
> # (ie. polarity) 
> data_s1 <- data_low_vision %>%
+    filter (subject == "s1")
> 
> # plot the MNREAD curve using ONE GROUPING ARGUMENT (ie. polarity)
>  ## Not run:  mnreadCurve(data_s1, ps, vd, rt, err, polarity)  
> 
> #------
> 
> # restrict dataset to two subject (s1 & s2) and plot the MNREAD curves using TWO GROUPING ARGUMENTS 
> # (ie. subject and polarity) 
> data_s2 <- data_low_vision %>%
+    filter (subject == "s1" | subject == "s2")
> 
>  ## Not run:  mnreadCurve(data_s2, ps, vd, rt, err, subject, polarity)  
> 
> #------
> 
> # Once created, the MNREAD curve can be customized as needed using ggplot2, 
> # for ex., by adding the number of errors for each sentence on top of the curve
> 
> # plot the MNREAD curve 
> my.plot <- mnreadCurve(data_s1, ps, vd, rt, err, polarity)
> 
> # display my.plot
> print(my.plot)
Error in Summary.unit(c(4.4, 4.4), na.rm = FALSE) : 
  VECTOR_ELT() can only be applied to a 'list', not a 'double'
Calls: print ... render_strips -> build_strip -> ggstrip -> Summary.unit
Execution halted