Error Estimation for Refractive Index of Dielectric Material

[Mechdude]

Homework Statement

i did a lab on determination of refractive index of an opaque dielectric material, using the brewster angle. We took a couple of readings on a spectrometer at the position of complete extinction,
now how do i get the error estimate ? The angles were taken to the nearest minute

Homework Equations

tan \theta_B = \frac {n_t}{n_i}

The Attempt at a Solution

 

[lanedance]

you could look at dreivatives

you have the refractive index calculated in terms of the angle
n = f(\theta)

for a small change in angle
d \theta

what is the corresponding change in refractive index?
dn = \frac{df(\theta)}{d\theta}d\theta