Xiaoying and her parents plan to travel abroad, and initially choose Yan 'an, Xi, Hanzhong and Ankang. Because of the rush of time, they can only

∫ * * There are 16 possible results. Xiaoying and her mother randomly touched the ball once and only found 1 case.

∴ Xiaoying and her mother randomly touch the ball once, and the probability that both of them touch the white ball is:116;

(2) From (1): * * There are six possible results: Xiaoying and her mother randomly touched the ball once, and at least one person touched the yellow ball in seven cases.

Xiaoying and her mother touch the ball at random once, and the probability that at least one person touches the yellow ball is 7 16.