Boxplot Alignment problem when knitting Pdf

[mpoursadegh]

Hello,
I'm trying to plot boxplot using boxplot() from base package. When I run the code chunk in R markdown it works fine but when I knit it to pdf the figure goes to the right like this:

The code chunk is pretty simple:
boxplot(a$medSalary,horizontal = TRUE, names = 'Projected Salary',xlab='[$]',las=1)
And BTW, I'm using TinyTex.
Thanks in advance

[technocrat]

Fortunately, Rmd can handle HTML markup. (Had to do a screenshot because the discourse platform would otherwise use it as format instructions)

[mpoursadegh]

Thank you very much!