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Distribution of IQ scores and standard deviation

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1.) Test one: mean is 80 and standard deviation is 9. Mark scores 91

Test two: mean is 77 and standard deviation is 6. Mark score 87

Find the percentile for all

Which test Mark did better? Why?

2.) What is the the standard deviation for IQ tests? If someone's IQ is 140, how many standard deviation is it above the mean?

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Solution Summary

This solution helps explore the following questions:
How to compare distributions with different standard deviations?
How to compute standard deviation for IQ scores?

Solution Preview

The percentile can be calculated from a standard normal distribution table.

You can find one here: ...

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