From a high school science teacher,

Once you get the slope lets say for example the student generates three lines one best fit line for Control, another for 1 percent of tested solution and 5 percent of tested solution. We have three slopes to compare. Is there a way of statistically comparing the slopes to see if there is a difference among slopes that is greater than by chance?

Sample data

Cumulative Planaria Crossing Line as a measure of activity over 5 minutes using different solutions

Time (min) Control Sugar Nicotine

3 10 12 8

6 22 17 14

9 30 25 20

12 42 30 24

15 56 37 31

Thanks

rich