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Example Questions
Example Question #1 : How To Find The Quartiles For A Set Of Data
Obtain a normal distribution table or calculator for this problem.
Approximate the -percentile on the standard normal distribution.
The -percentile is the value such that
percent of values are less than it.
Using a normal table or calculator (such as R, using the command qnorm(0.9)), we get that the approximate -percentile is about
.
Example Question #232 : Ap Statistics
Find the first and third quartile for the set of data
In order to find the first and third quartiles, we haave to find the 25th and 75th percentiles, respectively.
To find the percentile, we find the product of
and the number of items
in the set.
We then round that number up if it is not a whole number, and the
term in the set is the
percentile.
For this problem, to find the and
percentile, we first find that there are 14 items in the set. We find their respective products to be
and
As such, the and
percentiles are the fourth and eleventh terms in the set, or
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