Science Buddies: "Ask an Expert"

Recently, I've come across a roadblock. I have created a science fair topic about the absorption of different materials in soil, and to compare them, to see if making a more renewable source can be effective. However, after doing 3 rounds of testing over 4 days, I don't know exactly how to create the math for the project. I want to create a percentage that sort of shows how much more effective my absorbent was compared to other non-renewable absorbents in soil.

I'll add the data as a attachment, as it's shown as a percentage, since the way i'm measuring each of their effectiveness is through the percentage of their moisture contents. I already have a graph made, but I'm just not too sure about the next step.

I would really appreciate any help at this point, since my science fair deadline is very soon.

To whoever answers this question, thank you!

Sorry, in case I was being too vague earlier, I have already created a percentage of how much the moisture content % goes down for each material, peat moss, my absorbent, and regular soil as the control. I was just wondering if there was a way to "compare" two sets of data to mine, so to show how mine is better than the others in a sort of way?

Hello,
One way in which you can compare the significance of data is by using the standard error of the mean (SEM). this is a formula that you can find anywhere (many calculators are available on online where you enter in values) that calculates the potential error in data. You plot this with error bars, where you add and subtract the SEM from your value and plot a line the see the variance. If these bars overlap with the bars at a different data point, the results are not significant. This can be used to show how other data is not significant while your is (there's no overlap in error bars). Let me know if you would like a further explanation.

Hello Dog Lover,
I agree with the expert's suggestion that the s.e.m. (standard error of the mean) can provide a useful measure of the variability you observed for a particular experimental condition (for example, absorbed moisture measured for each of several different samples of your absorbent).

However, as I read your post, it is not clear to me how many different, independent samples of your absorbent, or peat moss, or soil were tested in your experiment.

Also, when you refer to "percentage" in your graph, is that a measure of "percent absorption" in a specific test sample (absorbent, peat moss, soil) or is that a summary measure of percent of samples, if you had multiple samples of each material?

Depending on how you set up your experiment, there could be other statistical methods to evaluate your results!

Thanks for sharing your graph and thanks in advance for sharing more details about your projects!

Madeline