Sort of Ribbed.
I used Jameson's Shetland Wool in worsted. I think it's colour number 65 on the Jumper Weight colour card. It's knit in 5mm (US size 8) needles and takes one skein or less depending on the size you want. This one fits a woman's size medium head.
Cast on 80 sts (it needs to be an even number if you are making a larger or smaller hat). Divide over 4 needles and join to knit in the round.
Round 1: K1, P1 around
Round 2: Knit
Repeat those two rounds to desired length. I knit to about 5". End with a knit round.
Begin decrease rounds. You will be decreasing on the K1, P1 round. Divide the number of stitches on each needle in half. The middle four stitches will be the decrease stitches.
Work until you get to the first two of the middle four. If the last stitch you worked was a purl stitch, you will want your decrease to look like a knit stitch. Do this by cabling the two stitches so that the knit stitch stays in the front, then knit the two together. The next two will be a purl. Cable the two stitches so that the purl stitch stays in the front and purl the two together. (If the last stitch worked before the decrease stitches was a knit, you will need to keep the purl stitch in front for the first decrease and the knit stitch in front for the second decrease.)
Knit the next round.
Repeat those two rounds until you have four stitches left on each needle. Break yarn and thread tail through remaining live stitches, draw up tight and weave in end to secure. Weave in cast on end.
Enjoy new hat!