A woman and man have approached you for genetic counseling and are concerned about a hereditary form of deafness in their family. Both have normal hearing and there are no children. The woman's father has autosomal dominant sensory-neural deafness. Assume he is heterozygous. This hearing impairment displays onset at about age 10, and penetrance appears to be about 70%. There is no family history of deafness among the man's relatives. What is the probability that the woman is a carrier of the deafness allele