Standard normal distribution question!!
assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation 20. Find P15, which is the IQ score separating the bottom 15% from the top 85%.
how do i find this!

Question

Standard normal distribution question!!
assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation 20. Find P15, which is the IQ score separating the bottom 15% from the top 85%.
how do i find this!

anonymous · Answer

You're looking for the 15th percentile. You need to find the z-score corresponding to a proportion/probability of 0.1500, then use the z-score formula to solve for x.

anonymous · Answer

This site is rather good for straight-forward notes and formulas: http://stattrek.com/probability-distributions/standard-normal.aspx?Tutorial=Stat

anonymous · Answer

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