# Both t.test ; why different p-values??t.test()&ggboxplot()

Welcome to the community!

I'm unable to reproduce this odd and undesirable behaviour. See below:

``````library(ggpubr)

ggboxplot(data = ToothGrowth,
x = "supp",
y = "len") +
stat_compare_means(method = "t.test",
paired = FALSE,
method.args = list(alternative = "greater"))
``````

``````
t.test(formula = (len ~ supp),
data = ToothGrowth,
alternative = "greater",
paired = FALSE)
#>
#>  Welch Two Sample t-test
#>
#> data:  len by supp
#> t = 1.9153, df = 55.309, p-value = 0.03032
#> alternative hypothesis: true difference in means is greater than 0
#> 95 percent confidence interval:
#>  0.4682687       Inf
#> sample estimates:
#> mean in group OJ mean in group VC
#>         20.66333         16.96333

t.test(x = ToothGrowth\$len[ToothGrowth\$supp == "OJ"],
y = ToothGrowth\$len[ToothGrowth\$supp == "VC"],
alternative = "greater",
paired = FALSE)
#>
#>  Welch Two Sample t-test
#>
#> data:  ToothGrowth\$len[ToothGrowth\$supp == "OJ"] and ToothGrowth\$len[ToothGrowth\$supp == "VC"]
#> t = 1.9153, df = 55.309, p-value = 0.03032
#> alternative hypothesis: true difference in means is greater than 0
#> 95 percent confidence interval:
#>  0.4682687       Inf
#> sample estimates:
#> mean of x mean of y
#>  20.66333  16.96333
``````

Created on 2019-03-31 by the reprex package (v0.2.1)