I think he means the index value. Once you have a list of all your values, find the length and minus 1 then get your indexes for the quartiles like below

```
myList = (1,2,4,5,7,8,9,12,13,13,14)
nodeCnt = len(myList) - 1
q1_ndx = nodeCnt * .25
q2_ndx = nodeCnt * .5
q3_ndx = nodeCnt * .75
print q1_ndx, q2_ndx, q3_ndx #Result is 2.75, 5.5, and 8.25
```

Once you have these values, if it is a fraction, round up and round down to get the index values needed to average the actual values. For example, for q1 in my script, the index value is 2.75. There is no 2.75 index, so round up and down to get 2 and 3. Quartile 1 will be the average of indexes 2 and 3

```
q1 = (myList[2]+myList[3]/2)
```

**EDIT**

An easier way is to use `system.math.percentile()`

```
myList = (1,2,4,5,7,8,9,12,13,13,14)
q1 = system.math.percentile(myList,25)
q2 = system.math.percentile(myList,50)
q3 = system.math.percentile(myList,75)
```