Answer:
The percentile is calculated with the following probability:
And using the z score we got:
So then we can conclude that 31 represent approximately the percentile 81 on the distribution given
He scored better than about 80.98 % of all MCAT takers.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:
Where and
And for this case we have a score of 31
The percentile is calculated with the following probability:
And using the z score we got:
So then we can conclude that 31 represent approximately the percentile 81 on the distribution given
He scored better than about 80.98 % of all MCAT takers.
