Missing column `day` in `perform_simulation()`

[IronistM]

Description When running the examples provided in the R Notebook I get the following error, day is not a known column for perform_simulation() function.

Reproducable example The following is the output of the run

library(splittestr)
library(plyr)
library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:plyr':
#> 
#>     arrange, count, desc, failwith, id, mutate, rename, summarise,
#>     summarize
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
library(tidyr)
library(broom)
library(ggplot2)

nreps <- 5000

set.seed(2015 - 08 - 07)
sim_no_difference <- data_frame(replicate = seq_len(nreps)) %>%
  mutate(proportion_A = .001,
         effect = 0,
         per_day = 10000) %>%
  perform_simulation()
#> Error in grouped_df_impl(data, unname(vars), drop): Column `day`: unknown