Final answer:
Fahrenheit above 60 degrees, there is an estimated increase of 3.58 hatched eggs on average. The slope of 3.58 in the regression line indicates that for every degree Fahrenheit increase above 60 degrees, there's an average estimated increase of 3.58 frog eggs hatched per day.
Step-by-step explanation:
The slope of the least-squares regression line is a value that describes the rate of change between the independent and dependent variables. In the given equation ý = 15.66 +3.58x, where x represents the number of degrees by which temperature exceeds 60 degrees Fahrenheit and y represents the number of eggs hatched per day for frogs, the slope is 3.58. Therefore, the correct interpretation of the slope in this context is that for each increase of one degree Fahrenheit above 60 degrees, there is an estimated increase of 3.58 hatched eggs on average.