Z-Expansion fit using some data-thief'd results.
- Extract results from json files.
- Individually fit each result to Z-Expansion.
- Plot each fit as a function of Q2.
- At each Q2 point take values from each of the fits, take average and standard dev.
- Fit the average and std lines to Z-Expansion. Extract error from difference in std and avg coeffs.
- Calculate covariance, print results.