# How to plot this graph with std deviation? - (Jan/06/2009 )

Hi all

I am stuck with plotting my data with the error bars.

I have triplicate for 4 kinds of Sample. I need to plot graph with average of each, now I have no idea how to do it in excel,

For example I have 4 kinds of inhibitor and have repeated each one atleast 3 times;

Inh1 - Value1, 2, 3

Inh2 - Value1, 2, 3

Inh3 - Value1, 2, 3

Inh4 - Value1, 2, 3

When i plot a graph with averages of all 4 types of inhibitor and then use STDEV function in excel, it calculates deviation among these avaragevalues of inhibitor. Whereas I actually want Std dev between different values of same INhibitor* I HOPE I AM CLEAR)

Please help me with this

Regards

hi nrk,

if i understand right, i think what you need to do are boxplots, this link has a similar topic, i hope you find it useful:

http://www.protocol-online.org/forums/inde...showtopic=39231

cheers.

You can just select the values for which u need to calculate standar deviations in EXCEL.

Hope it is clear.

Hope it is clear.

I can calulate the std dev of averages in excel, but then how to plot the graph showing averages with error bars of all the inhibitors??

Thanks

i, personally, would never use Excel for anything constructive, but since you're using it, here is what you need to do: first calculate the average of the values for each inhibitor, then calculate the standard deviation for these values. so now, you have a list of the inhibitor names, next to them a list of the averages for each inhibitor, and next to that a list of the standard deviation for each inhibitor. then plot the values, selecting column plots, specify the x-variable as your inhibitor list and the y-variable as the list of averages you calculated. then finish plotting the graph, and right click on the columns to format data series. then go to the y-error bars tab and at the bottom, click the button next to custom. there will be two windows next to custom, one with "+" in front of it (hereafter referred to as + window) and the one below the + window will have a "-" in front of it. if you click on the little button on the right hand side of the + window, it will allow you to select a series of values, select the list of standard deviations you calculated. then do the same with the - window. this will give you what you want i think