Scope: Lectures 13-14. Four questions; submit derivations and code/output where requested.
State units and model assumptions. Keep unrounded values in code and round only in your final communication. Revisions and resubmissions are encouraged.
Question 1
Using the included Pantheon+ subset, fit only a constant intercept at fixed fiducial distance-redshift shape with the full covariance. Report beta, its GLS standard error, and chi-square before/after fitting.
Work to show: equations, units, assumptions, and a reproducible computation where requested.
Question 2
State why the fitted intercept is conditional on this teaching subset and does not estimate Omega_m or reproduce a published H0 constraint.
Work to show: equations, units, assumptions, and a reproducible computation where requested.
Question 3
Choose one Planck, BOSS, Pantheon+, or DES summary row. Write its probe, observable, model assumptions, uncertainty convention, source key, and provenance level.
Work to show: equations, units, assumptions, and a reproducible computation where requested.
Question 4
A collaborator proposes combining all four probes by adding inverse variances. Identify at least four missing ingredients required before that joint inference is defensible.
Work to show: equations, units, assumptions, and a reproducible computation where requested.