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"What percent of the population has an intelligence quotient below 100? A. 75% B. 50% C. 35% D. 10%"
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Answer

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Step 1:
Let's solve this step by step:

Step 2:
: Understand the IQ Distribution

- IQ scores follow a normal distribution - The mean (average) IQ is 100 - The standard deviation is typically 15 points

Step 3:
: Interpret the Normal Distribution

- In a normal distribution, 50% of the population falls below the mean - This means exactly 50% of people have an IQ below 100

Step 4:
: Verify the Calculation

- The standard normal distribution is symmetrical - The mean (100) divides the distribution exactly in half - This means precisely 50% of people have an IQ below 100

Step 5:
: Eliminate Incorrect Answers

- 75% is too high - 35% is too low - 10% is far too low

Step 6:
: Select the Correct Answer

- The answer that matches our calculation is B. 50%

Final Answer

Key Insight: In a normal distribution, exactly half the population falls below the mean, which for IQ is 100.