This is a beginner scarf for knitters just learning to do 1x1 rib. To practice your knits and purls, make a ribbed scarf.
You can knit this scarf in either aran or bulky weight yarn. Using bulky yarn will make the project go faster, and the scarf will be a little bit more... well, bulky.
The scarf will be 4.5 inches wide whether you use aran or bulky yarn because you will be casting on a different number of stitches to compensate for the yarn thickness.