# Median Volume Displaced

1. Feb 7, 2015

### Staff: Mentor

1. The problem statement, all variables and given/known data
A question in my chemistry 151 lab book:

A student measures the volume of water displaced by the same metal sample as 5.4 mL, 5.8 mL, and 5.5 mL for his three determinations. Determine the median volume.

2. Relevant equations
Unknown or N/A

3. The attempt at a solution
How do you find the median volume? Per wiki's explanation of what a median is, the median of the three numbers is the middle number after arranging them in order from lowest to highest, so in this case 5.5 mL. However I'm not sure this is what the question is actually asking. My instructor went over experimental error and uncertainty, but I don't remember anything about the median of a group of numbers and I can't find an explanation in either my textbook or my lab book.

Is it really just a simple as finding the middle of the three values, or have I misunderstood something? It just seems like too simple of a question if its really just the middle number.

2. Feb 7, 2015

### SteamKing

Staff Emeritus
That's all the median is: the sample in the middle of a series of different samples.

In survey data, particularly concerning economics, you'll find discussions of things like 'median income', which is just the income in the middle of the sampled incomes from a group of individuals.

Although the 'median' appears to be a trivial concept, it is actually much more useful than it seems:

http://en.wikipedia.org/wiki/Median

3. Feb 7, 2015

### Staff: Mentor

Alright. Thanks Steamking!