Merge pull request #171 from albhasan/numbering_of_challenge_158

The challenges' numbering was updated

Author: coopermkr

episodes/03-data-structures-part1.Rmd

@@ -373,7 +373,7 @@ class(categories)
 
 :::::::::::::::::::::::::::::::::::::::  challenge
 
-## Challenge
+## Challenge 3
 
 Can you guess why these numbers are used to represent these countries?
 
@@ -389,7 +389,7 @@ They are sorted in alphabetical order
 
 :::::::::::::::::::::::::::::::::::::::  challenge
 
-## Challenge 3
+## Challenge 4
 
 Convert the `country` column of our `nordic` data frame to a factor. Then try
 converting it back to a character vector. 
@@ -402,7 +402,7 @@ Remember that you can reload the `nordic` data frame using
 
 :::::::::::::::  solution
 
-## Solution to Challenge 3
+## Solution to Challenge 4
 
 Converting character vectors to factors can be done using the `factor()` 
 function:
@@ -508,7 +508,7 @@ str(nordic[1, ])
 
 :::::::::::::::::::::::::::::::::::::::  challenge
 
-## Challenge 4
+## Challenge 5
 
 There are several subtly different ways to call variables, observations and
 elements from data frames:
@@ -527,7 +527,7 @@ Try out these examples and explain what is returned by each one.
 
 :::::::::::::::  solution
 
-## Solution to Challenge 4
+## Solution to Challenge 5
 
 ```{r, eval=TRUE, echo=TRUE}
 nordic[1]