# 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)

Regards

-nrk-

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.

-toejam-

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

Hope it is clear.

-newarray-

QUOTE (newarray @ Jan 6 2009, 10:50 AM)
You can just select the values for which u need to calculate standar deviations in EXCEL.

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

-nrk-

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

-mimi222-