Since you have 2 different sizes of needles, this pattern gives you two different gauges according to the size of the needles. The sample should be done in Stockinette (1 row plain, 1 row purl). St stands for stockinette, st for stitch
Size 13 needles in Stockinette stitch 12 st=4 inches
Size 11 needles in Stockinette stitch 19 1/4 stitches , 14 2/3 rows = 4 inches
A sample is always done in Stockinette unless a specific indication is given. The sample is done to ensure you have the right size of needles according with your yarn .
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