Double / single backticks for inline R code in an Rmarkdown file

Dear All,

I am reading this file :-

https://rmarkdown.rstudio.com/lesson-6.html

My query is : In line 14 of the above file, ie.

The [marmap](https://cran.r-project.org/web/packages/marmap/index.html)
package provides tools and data for visualizing the ocean floor. Here is an
example contour plot of marmap's ``r params$data`` dataset.

Should not the phrase rparams$data be within SINGLE backticks ?

Do I misunderstand?

Thank you,
Ashim