Question 41749
Set up a graph.  The x-axis is the temperature. The y-axis are the chirps.  Plot the graph according to the data:
(x-axis) Temp (ºC):  18  8 15 14 10  7 14  6 14  9 14 13 15 
(y-axis)# Chirps:    20 17 18 18 16 16 17 15 16 15 17 16 17
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Plot these points: (18, 20), (8, 17), (15, 18), (14, 18), (10, 16), (7,16), (14, 17), (6, 15), etc.
Even though the points are somewhat scattered, draw a "best-fit" line through the cluster of points.
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Next, using the formula N = 0.281t + 13.4, plug in each value for the temperature (x)and see what you get for the value of the chirps.  Plot these new points on the same graph (maybe in a different color ink). Compare both lines and see how close they are.
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Example:   N = 0.281t + 13.4
Plug in the first temperature value of 18 taken from the old point of (18,  20):
N = 0.281(18) + 13.4
N = 18.458.  The new point is (18, 18.458) which is pretty close to the old point of (18, 20)
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Take another old point and plug in the x-value into N = 0.281t + 13.4
Use the x value from (8, 17):
N = 0.281(8) + 13.4
N = 15.64.
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This new point of (8, 15.64) is pretty close to the old point of (8, 17).  Plot (8, 15.64).
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Continue to plug in the temperature and plot the new points.  Compare the old and the new plotted lines.

I hope this helps.  It isn't as hard as it seems  -- it is just a lot of work!!!