Posted by Leigh on .
I need help with the first and third quartiles of 15,17,19,22,23,27,31,36,43,44,48,54,57
is the answer 20.5;46 or 20.5;48

Math 
PsyDAG,
The first quartile defines the lowest 25%, while the third quartile defines the highest 25% (lowest 75%). With 13 scores arranged from lowest to highest, the 25% is between the 3rd and 4th scores and 75% between the 10th and 11th scores.
I hope this helps. Thanks for asking.