Question

how to find the first quartile of a set of data

Answer 1

Step 1. Get it in order least to greatest
Step 2. Find the median
Step 3. Treat the first half of the data as it's own set of data and find the median of that

That's your first quartile

Answer 2

i thought i find the median then add that to the lowest value and didvide by 2. thats wrong?

Answer 3

This is another option, however the first option is probably easier.

1, 3, 5, 7, 9, 11, 13, 15, 17.
The median is 9.

1, 3, 5, 7, 9.
The median of the first quartile is 5.