# Assessment Instructions: Problem Set 07 — Large-Scale Structure and Observational Cosmology

## Inputs to Inspect
Student submission, this problem set, the solution key, the corresponding lecture slides/notes, and the referenced dataset(s) under `materials/ASTR230/data/`.

## Grading Standard
Award credit for correct method and units first, then for the specific numeric result. A student who shows correct reasoning with a small arithmetic slip should receive most of the available credit; a student with a correct-looking number but no visible reduction steps should not.

## Problem-Level Criteria
- Problem 1: 15 points — Correct Hubble’s law application.
- Problem 2: 15 points — Correct Hubble time for both endpoints and correct inverse-relationship reasoning.
- Problem 3: 15 points — Correct virial-type mass reasoning and a valid independent line of evidence.
- Problem 4: 15 points — Correct, specific explanation of the CMB’s role in confirming the Big Bang over the Steady State model.

## Resubmission Policy
Students may resubmit within one week of receiving feedback. A resubmission must show a corrected derivation, not only a corrected final number, and should reference the specific feedback comment it addresses. Regrade to a maximum of 90% of the original point value unless the error was a grading mistake.

## Common Errors to Flag
- Confusing the direction of the H0-to-age relationship (assuming higher H0 gives an older universe).
- Citing rotation curves again as the "independent" evidence for Problem 3 rather than a genuinely different method (lensing, CMB, etc.).
- Describing the CMB as evidence against the Steady State model without explaining what specific prediction distinguished the two models.