IQ is calculated by whom?

Appeared in: Maharashtra CHO - 2020

Explanation

The correct formula for calculating the Intelligence Quotient (IQ) is by dividing the Mental Age (MA) by the Chronological Age (CA) and multiplying the result by 100.
This formula, proposed by William Stern, creates a ratio that compares an individual's intellectual performance to the average performance for their actual age.
A score of 100 indicates that the mental age is equal to the chronological age, which is considered average.
Scores above 100 suggest a higher-than-average intellectual rate of development, while scores below 100 suggest a slower rate.

Option A: This option incorrectly uses addition. Adding mental age and chronological age would result in a meaningless, inflated number that does not represent a ratio of intellectual development.
Option C: This option incorrectly uses multiplication. Multiplying mental and chronological ages would produce an exponentially large and nonsensical value, not a standardized quotient.
Option D: This is identical to the first incorrect option, simply with the terms reversed. It incorrectly uses addition instead of division, which is fundamental to calculating the IQ ratio.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculation of Intelligence Quotient (IQ) as background academic context rather than a clinical decision trigger.
Understanding how IQ is calculated helps nurses appreciate the basis of cognitive assessments, which are crucial for identifying developmental delays or intellectual disabilities in pediatric patients.
Knowledge of a patient's cognitive level (whether formally measured by IQ or informally assessed) allows nurses to tailor communication, patient education, and consent discussions to an appropriate level of understanding.
What if a patient has a documented intellectual disability (low IQ)? The nurse must adapt their care plan by using simple language, visual aids, and involving family or caregivers more actively to ensure comprehension and adherence to treatment.

How to Approach the Question

First, identify the core concept of the question, which is the formula for 'IQ' (Intelligence Quotient).
Recall the definition of IQ as a 'quotient' or 'ratio' comparing two types of ages.
Analyze the components given: 'Mental Age' and 'Chronological Age'. A ratio is formed by division.
Examine the options to find the one that correctly represents this division: (Mental Age / Chronological Age).
Confirm the final step, which is multiplying by 100 to express the ratio as a standard score.
Eliminate options that use incorrect mathematical operations like addition or multiplication.

Concept Tested & Keywords

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E6 Psychology Baron Misra 5e Part 2 p. 50-52

E6 Psychology Morgan King 9e Part 2 pp. 129-131, 128-130

Practise the full Maharashtra CHO - 2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.