Marmots are large squirrels that hibernate in the winter and come out in the spring. Figure 1.28 shows the date (days after Jan 1) that they are first sighted each year in Colorado as a function of the average minimum daily temperature for that year. 

(a) Find the slope of the line, including units. 

(b) What does the sign of the slope tell you about marmots? 

(c) Use the slope to determine how much difference 6◦C warming makes to the date of first appearance of a marmot. 

(d) Find the equation of the line.

Figure 1.28

day of first marmot sighting 150 140 130 120 110 100 90 mean minimum 8 10 12 14 16 18 20 22 24 temperature (C)