In bowl, toss together cabbage, carrot, onion and celery. In small bowl, stir together yogurt, mayonnaise, vinegar, mustard, sugar, salt and pepper. Stir into cabbage mixture; toss well. [Coleslaw can be refrigerated in airtight container for up to 2 days] Variation: add chopped sweet pepper, small broccoli florets or any other vegetables you have on hand. Per Serving: about 65 calories, 2 g protein, 3 g fat, 9 g carbohydrate