Studies show that male and female mice react differently to a set of experiments. Specically, 70% of female mice react positively to the experiments, whereas only 40% of males react positively. A group of 20 mice, including 15 female and 5 male, were subjected to these experiments, and their reactions were recorded in a questionnaire. A response picked at random from the 20 mice was negative. What is the probability that it was that of a male mouse