Question

The mean score for a person with an average IQ is ___. a. 70 b. 130 c. 85 d. 100

Short answer

The correct answer is d. 100

Step-by-step solution

Understand the Question

The exercise is asking for the usual or 'mean' score for an IQ test. Knowing that IQ scores are standardized, with the bulk of scores centering around a specific figure, this is about understanding what that 'usual' or centre figure is.

Understand IQ Scoring

IQ scores are standardized to have a mean of 100 and standard deviation of 15. This means that the most common or 'average' score is 100.

Identify the Correct Answer

Based on the information from Step 2, the correct answer must be 'd. 100'

Key concepts

IQ Scores

IQ scores are a numeric representation of a person's cognitive abilities compared to the general population. They are derived from standardized tests specifically designed to assess human intelligence. These scores are often used to identify intellectual potential or difficulties.

• IQ scores aim to reflect an individual's ability to learn, reason, solve problems, and understand complex ideas.
• An IQ score is not fixed; it could change over time due to various factors such as education and environment.
• The scale of IQ scores is designed to have a mean of 100, placing most people around this number.

These scores are a common tool in both educational settings and psychological evaluations. It's important to understand their limitations, as they don't account for all forms of intelligence, such as emotional or practical intelligence.

Psychometrics

The field of psychometrics involves the theory and technique of psychological measurement. This includes measuring knowledge, abilities, attitudes, and personality traits. Psychometrics is crucial for the development and validation of IQ tests:

• Psychometricians ensure that IQ tests are valid and reliable, meaning they truly measure what they claim to measure and produce consistent results over time.
• They apply statistical models to ensure that test scores are accurate representations of the individual's abilities.
• Through psychometric analysis, tests are refined, ensuring a fair assessment across different demographic groups.

By understanding psychometrics, we can appreciate the robustness of IQ testing and its role across various fields, including education, medicine, and psychological research.

Standard Deviation

Standard deviation is a statistical measure that quantifies the amount of variation or dispersion in a set of data values. In the context of IQ scores, it provides insight into how much individuals' scores typically differ from the mean score. In standardized IQ tests:

• The standard deviation is typically set at 15.
• This means that scores within one standard deviation (15 points) above or below the mean (100) capture the majority of the population.
• About 68% of people will have an IQ score between 85 and 115, falling within one standard deviation from the mean.

Understanding standard deviation helps in interpreting IQ scores, as it gives context to where a particular score lies in comparison to the broader population.

Standardized Testing

Standardized testing refers to any form of test that requires all test takers to answer the same questions, or a selection of questions, in a uniform manner. IQ tests are a prime example of standardized testing. These tests are crafted to have consistent conditions:

• They allow for the comparison of scores across different individuals in a reliable way.
• Tests are administered in a consistent environment, which helps reduce variation caused by external factors.
• Results are used to make inferences about an individual's abilities relative to a population.

Standardized testing is essential for evaluating and benchmarking individuals’ cognitive abilities on a large scale. Despite criticisms, such as potential cultural biases, they remain a key method in educational and psychological assessments.