Fix typos

_episodes_rmd/01-intro-rstudio.Rmd

@@ -42,7 +42,7 @@ on if needed. You can copy-paste into the R console, but the RStudio script
 editor allows you to 'send' the current line or the currently selected text to
 the R console using the <kbd>Ctrl</kbd>+<kbd>Return</kbd> shortcut.
 
-At some point in your analysis you may want to check the content of variable or
+At some point in your analysis you may want to check the content of a variable or
 the structure of an object, without necessarily keep a record of it in your
 script. You can type these commands directly in the console. RStudio provides
 the <kbd>Ctrl</kbd>+<kbd>1</kbd> and <kbd>Ctrl</kbd>+<kbd>2</kbd> shortcuts allow you to jump between the script and the

_episodes_rmd/04-making-packages-R.Rmd

@@ -175,7 +175,7 @@ After `Install and Restart`-ing again, looking up the documentation should work.
 What exactly does `roxygen2` do? It reads lines that begin with `#'` as the function documentation for your package.
 Descriptive tags are preceded with the `@` symbol. For example, `@param` has information about the input parameters for the function.
 
-### Exporting "user-level" function
+### Exporting "user-level" functions
 
 We haven't talked about the `NAMESPACE` file yet! It belongs to the package skeleton,
 and was set up by RStudio with an `exportPattern`. Any file name in `R/` that
@@ -193,7 +193,7 @@ Learn more about this from the ["R packages" book][r-pkgs-name].
 
 ### Finishing up
 
-Please take a look at RStudio's `Files` panes now. The `/man` directory should
+Please take a look at RStudio's `Files` panes now. The `man` directory should
 now contain one LaTeX-like formatted `.Rd` file for each function.
 
 In case you learned about Git already, also view the `.Rd` files in RStudio's