**Probability Basics**: The skill of Probability Basics involves understanding the fundamental principles and concepts related to probabilities, including calculating probabilities of events, using probability rules, and understanding the different types of probability distributions. This skill should be measured in the test to assess the candidate's foundational knowledge and understanding of probability, which is crucial in various fields such as statistics, data analysis, and decision making.

**Combinatorics**: Combinatorics is the skill of counting and arranging objects or events. It encompasses concepts such as permutations, combinations, and the principles of counting. Measuring this skill in the test helps evaluate the candidate's ability to solve problems involving arranging, selecting, and counting objects, which is essential in various mathematical and statistical applications.

**Random Variables**: The skill of Random Variables involves understanding the concept of random variables and their probability distributions. Random variables are variables whose values depend on the outcome of a random event. Measuring this skill in the test can assess the candidate's ability to analyze and interpret random phenomena, as well as apply probability distributions to model real-world situations.

**Joint Distributions**: Joint Distributions refer to the probability distribution of two or more random variables. This skill involves understanding the joint probability distribution, conditional probability, and related concepts. Including this skill in the test helps evaluate the candidate's grasp on modeling and analyzing the relationships between multiple random variables, which is essential in various fields such as machine learning, finance, and operations research.

**Quantitative Aptitude**: Quantitative Aptitude is the skill of solving mathematical problems and analyzing numerical data. It encompasses various mathematical concepts, including arithmetic, algebra, geometry, and graphs. Measuring this skill in the test allows recruiters to assess the candidate's ability to analyze and solve quantitative problems, which is valuable in roles that require data analysis, financial analysis, and problem-solving.

**Numerical Reasoning**: Numerical Reasoning is the skill of understanding and applying logical and analytical reasoning to numerical information. It involves interpreting and analyzing numerical data, identifying patterns, and making logical deductions. Including this skill in the test helps evaluate the candidate's ability to analyze and draw conclusions from numerical information, which is important in roles that require critical thinking, problem-solving, and data interpretation.