Final answer:
The correct answer is option c. In this linear regression scenario with a dummy variable, the estimate of the slope is determined by the difference in the average values of y for men and women, which results in a slope estimate of -1.
Step-by-step explanation:
The question involves identifying the estimate of the slope in a simple linear regression where the dependent variable y is regressed on a dummy variable representing gender. Here, the dummy variable 'male' has a value of 1 if the individual is male and 0 otherwise. With the average values of y for men being 7.5 and for women being 8.5, respectively, we can deduce the slope by observing the change in the average value of y as the dummy variable switches from 0 (women) to 1 (men). The change in y (which is the slope) is 7.5 (male average) - 8.5 (female average), giving us -1.
Hence, the correct option is c. The estimate of the slope is equal to -1.