Metallicity

No matter how good your data is, and no matter how good your analysis technique is you can never have perfectly correct data. However you cannot simply acknowledge that and move on, you must figure out just for imperfect the data is. This process is often quite tricky and involves in depth understanding of the experiment as well as statistical analysis. In our case however, there is one element that is presenting the largest error.

Since each point on your graph is in fact an average of many points, what we can use as the error is the difference between the 
highest and lowest value within each bin.
 
 Go back and figure out what this difference is for each point and assign that value to each corresponding point. The simplest way to represent error on a graph such as this is through the use of error bars. 

Once you have this these values plotted you are finished with all of the plotting. All that is left now is to analyze the data.