From a set of thirteen marbles, six green and seven yellow, we choose one at random. a. What are the odds in favor of choosing a green marble? b. What are the odds against choosing a green marble? a. The odds in favor of choosing a green marble are \( \square: \square \). (Simplify your answers.)

To determine the odds in favor of choosing a green marble, we first identify the number of green and yellow marbles. There are 6 green marbles and 7 yellow marbles, making a total of 13 marbles. The odds in favor of selecting a green marble can be expressed as the ratio of the number of green marbles to the number of yellow marbles. This gives us \(6:7\). For the odds against choosing a green marble, we simply reverse the ratio. The odds against are the number of yellow marbles to the number of green marbles, which results in \(7:6\). So, the answers are: a. The odds in favor of choosing a green marble are \(6:7\). b. The odds against choosing a green marble are \(7:6\).