math115
posted by p .
Heres the problem find the first and third quartiles of the following set of numbers I put them in order 146,218,242,249,277,319,347,391,567 my answer is q1=230 and q3 =369 is this correct

If you used the following formula to calculate the quartiles, the answers are correct.
There are different ways to calculate quartiles. One that is widely used is to calculate the location of the sorted list, given by:
i=(1/4)*(n+1) where n is the number of observations.
According to the formula, n=9, so the quartiles are at locations 2.5 and 7.5, the values of which are obtained by interpolation.