The most useful analytical method when trying to identify groups with similar behavior or characteristics in a large population is classification. Classification is a technique that assigns data points to predefined categories or classes based on their features or attributes. Classification can help to discover patterns, trends, and relationships among the data and reveal the similarities or differences among the groups. Classification can also help to support decision making, prediction, or recommendation based on the data analysis. References:
* CISA ReviewManual (Digital Version), Chapter 3, Section 3.4.21
* CISA Online Review Course, Domain 2, Module 3, Lesson 12

The primary purpose of performing a parallel run of a new system is to validate the new system against its predecessor. A parallel run is a strategy for system changeover where a new system slowly assumes the roles of the older system while both systems operate simultaneously. This allows for comparison of the results and outputs of both systems to ensure that the new system is working correctly and reliably. A parallel run can also help identify and resolve any errors, discrepancies, or inconsistencies in the new system before the old system is discontinued.
The other options are not the primary purpose of performing a parallel run of a new system. A. To train the end users and supporting staff on the new system. Training is an important part of system implementation, but it is not the main reason for doing a parallel run. Training can be done before, during, or after the parallel run, depending on the needs and preferences of the organization. B. To verify the new system provides required business functionality. Verifying the business functionality of the new system is part of user acceptance testing (UAT), which is a formal and structured process of testing whether the new system meets the specifications and expectations of the users and stakeholders. UAT is usually done before the parallel run, as a prerequisite for system changeover. C. To reduce the need for additional testing. Reducing the need for additional testing is not the primary purpose of performing a parallel run, but rather a possible benefit or outcome of doing so. A parallel run can help ensure that the new system is thoroughly tested and validated in a real-world environment, which may reduce the likelihood of encountering major issues or defects later on.
However, additional testing may still be needed after the parallel run, depending on the feedback and evaluation of the users and stakeholders.
References:
* ISACA, CISA Review Manual, 27th Edition, 2019, p. 2471
* IS

Segregation of duties (SOD) is a core internal control and an essential component of an effective risk management strategy. SOD emphasizes sharing the responsibilities of key business processesby distributing the discrete functions of these processes to multiple people and departments, helping to reduce the risk of possible errors and fraud1.
SOD is especially important in IT security, where granting excessive system access to one person or group can lead to harmful consequences, such as data breaches, identity theft, or bypassing security controls2. SOD breaks IT-related tasks into four separate function categories: authorization, custody, recordkeeping, and reconciliation1. Ideally, no one person or department holds responsibility in multiple categories.
In a role-based environment, where access privileges are granted based on predefined roles, it is important to ensure that the roles are designed and assigned in a way that supports SOD. For example, the person who develops an application should not also be the one who tests it, deploys it, or maintains it.
Therefore, an application developer should not be assigned the roles of IT operator, system administration, or database administration, as these roles may conflict with their development role and create opportunities for misuse or abuse of the system. The only role that may be assigned to an application developer without violating SOD is emergency support, which is a temporary role that allows the developer to access the system in case of a critical issue that requires immediate resolution3. However, even this role should be granted with caution and monitored closely to ensure compliance with SOD policies.
References:
ISACA, CISA Review Manual, 27th Edition, 2019, page 2824
ISACA, CISA Review Questions, Answers & Explanations Database - 12 Month Subscription, QID 1066692 Hyperproof Blog, Segregation of Duties: What it is and Why it's Important1 Advisera Blog, Segregation of duties in your ISMS according to ISO 27001 A.6.1.23

A web proxy server for corporate connections to external resources reduces organizational risk by anonymizing users through changed IP addresses. A web proxy server is an intermediary between the web and client devices, that can provide proxy services to a client or a group of clients1. One of the main benefits of using a web proxy server is that it allows users to change their IP address and location, circumventing geoblocking and hiding their identity from the target website2.
Anonymizing internal IP addresses is important for online security, as it helps protect the organization from several threats. If an attacker controls a server that employees connect to, the outgoing IP address of the organization's router is logged on the server. This IP address can be used by the attacker to launch a denial-of-service (DoS) attack or to create more targeted attacks such as phishing2. With a web proxy server, the IP shown in web logs is the web proxy's, which means an attacker would not have access to the organization's router outgoing IP address2.
Anonymizing outgoing IP addresses is also important when carrying out sensitive actions online, such as law enforcement investigations or competitive intelligence. A web proxy server can help users avoid exposing their internal IP address that leads back to their organization, and instead use a third-party web proxy that provides more anonymity2.
The other options are not directly related to reducing organizational risk by using a web proxy server. Providing multi-factor authentication for additional security (option B) is a benefit of some web proxy servers, but it is not the main purpose of using a web proxy server3. Providing faster response than direct access (option C) is a benefit of some web proxy servers that cache content for better data transfer speeds and less bandwidth usage, but it is not directly related to reducing organizational risk1. Load balancing traffic to optimize data pathways (option D) is a benefit of some web proxy servers that distribute traffic across multiple servers, but it is not directly related to reducing organizational risk4.
References: 1: Proxy servers and tunneling 2: Multi-factor authentication: How to enable 2FA and boost your security 3: What Is Multi-factor Authentication (MFA) Security? 4: How it works: Microsoft Entra multifactor authentication