Question

IQ scores have a mean of 100 and a standard deviation of 15. What percentile corresponds to an IQ score of 115? Explain the steps you took to find the percentile.

Answer 1

The percentile that corresponds to an IQ score of 115 is 34.13 %

Explanation:

Here, we want to find the percentile that corresponds to an IQ score of 115.

To calculate this percentile, we start with making observations. From the question, we are told that the mean score is 100 while the standard deviation is 15.

Now we want to find the percentile for a score if 115. For a score of 115, we can see that the difference between this score and the mean is 15 which is exactly equal to the standard deviation.

What this means is that the score is within +1 SD of the mean.

For a score of within +1 SD of the mean, the percentile is 34.13%

A score at the mean is the 50th percentile, a score which is 1 SD above or below the mean has a percentile value of 34.13%

Please, I will like you to check the attachment to see how percentiles are valued given the number of standard deviations a particular value is from the mean.