Children were asked if they brushed their teeth regularly and, if so, with what brand of toothpaste. Children with dental caries (cavities) were identified. A statistician collected the records of children who brushed regularly and divided them into four categories of toothpaste. Brand A185 records; Brand B - 210; Brand C - 150; and all others, 105. Each of these four sets was then divided into children who had caries and those who did not. The results were: A, 38 with caries, 147 without; B, 45 with caries, 165 without; C, 32 with caries, 118 without; others, 30 with caries, 75 without. Suppose that of the 325 children who reported they didn't brush regularly, 40% had caries. Use this fact and the data in 10a to determine if brushing is related to dental health.