%matplotlib inline

import numpy as np
import matplotlib.pyplot as plt

f = [822, 693, 547, 518] 
y = f
v = [1.7, 1.28, .67, .395] 
df = np.array([.5, 5, 2, 1])
dv = np.array([.01, .01, .01, .05])

fit = np.polyfit(v, f, deg=1) 

def f(x,fit): return fit[0] * x + fit[1]

xfit = np.linspace(0,2)

plt.errorbar(v, y, yerr=df, fmt=".k")
plt.plot(xfit, f(xfit, fit))