Thank you! They are just a basic hat and the yarn itself creates the stripes. The yarn is Plymouth Encore Colorspun #7722. Scroll down on this page and you can see it in the skein. I got mine at my LYS.
For the adult size I cast on 80 and ribbed for about 2 inches then knit till the measurement was about 6-6.5" then decreased.
For the baby hat I cast on 60 and ribbed for 1-1.5" and knit till it was about 4.75" then decreased.
I usually cast on a multiple of 10 so decreasing is easy. Just k8, k2tog, pm around the hat. Knit a row plain then decrease by knitting to two stitches before the marker, slip marker around the hat. I go this way till I can just knit two together around the hat removing markers and then but yarn about 10 inches long. Thread through needle and go through stitches to remove from needles tighten the stitches then go through again and weave in. Easy peasy.