According to Auditing Standards,specific Relevant Aspects of an Internal Control

According to auditing standards,specific relevant aspects of an internal control system for making estimates include:
• Management communication of the need for proper accounting estimates.
• Accumulation of relevant,sufficient,and reliable data for estimates.
• Preparation of estimates by qualified personnel.
• Adequate review and approval by appropriate levels of authority.
• Comparison of prior estimates with subsequent results to assess the reliability of the estimation outcomes.
• Consideration by management of whether particular accounting estimates are consistent with the company's operational plans.
Required:
a.How would the auditor test these control activities over the production of estimates?
b.What substantive audit procedures would the auditor use to test the accounting estimates?