Explanation
Change Sets and Data Loader are deploy solutions that should be used to ensure skills-based routing is operational in Production. Change Sets are collections of metadata components that can be deployed from one Salesforce org to another. Change Sets can be used to deploy the configuration settings for skills-based routing, such as the skills, skill assignments, routing configurations, presence configurations, or service channels. Data Loader is a tool that can be used to insert, update, delete, or export records in Salesforce. Data Loader can be used to deploy the data records for skills-based routing, such as the work items, agents, queues, or routing priorities. Verified References: Service Cloud Consultant Certification Guide & Tips, Change Sets Overview, Data Loader Overview

Explanation
Number of cases created by site by month and Number of cases closed by a self-service user are reports that the contact center manager should present to executive management to demonstrate the success of recent self-service initiatives. These reports can help measure the impact and effectiveness of self-service channels, such as public website and community, on reducing the case volume and increasing the customer satisfaction.
For example:
Number of cases created by site by month is a report that shows the distribution and trend of case creation across different sources, such as phone, email, web, or community, over time. This report can help evaluate the adoption and usage of self-service channels by customers, as well as compare the case volume and workload between different channels.
Number of cases closed by a self-service user is a report that shows the number and percentage of cases that were resolved by customers themselves without agent involvement. This report can help assess the quality and effectiveness of self-service resources, such as knowledge articles, FAQs, forums, or chatbots, as well as measure the cost savings and customer satisfaction from self-service resolution.
Verified References: [Service Cloud Consultant Certification Guide & Tips], Create Reports and Dashboards for Self-Service