Hello, Please I need help with a statistical analysis. I don't know which statistical test to use. The study I did is as follows : an extraction by maceration of the leaves and stems of a plant and an ultrasonic assisted extraction of the leaves and stems as well. I then performed the following tests in triplicate (polyphenols, flavonoids, flavonols, condensed tannins and DPPH).
I want to make the following comparisons: - leaves with stems - Leaves (maceration) with leaves (sonication) - stems (maceration) with stems (sonication)
Hi Khawla,
you may use IC50 for each extract and compare them to a standard antioxidant (often vit C ), and the best statistical program for calculation of IC50 is GraphPad prism.
In experiments such as DPPH, ABTS, Beta-carotene, it is either compared to the standard antioxidant or made with the standard antioxidant equivalent if you want. This is your choice. In order to compare it with a standard antioxidant, it is necessary to experiment with an antioxidant such as BHA or BHT as an example during the experiment. At the end of the experiment, the test results are converted to IC50 values to be a standard result. Then it is checked how close the results of the samples are to the BHA or BHT. In the standard antioxidant equivalent (such as, ascorbic acid, trolox ), a calibration curve is drawn, then the quantities of the samples are determined from this formula. This is the most popular type of experiment lately.
If you want to look at the statistical difference between groups when all the work is done, you can do One-Way Anova if you have enough examples.
Ayad Palani Thanks for your time and responses. I have already compared the results of the DPPH test to a calibration range prepared with ascorbic acid. what I ask is in relation to the statistical study to see if my results are significant or not. I don't know exactly what statistical test should I use. a Student's t-test for independent sample or a one-way Anova or another test.
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Dear Khawla,
you can't do statistical analysis because you don't have a set of data. data of absorbance you have can not be used in statistical analysis. these data must be used to find IC50 (one value) , if the IC50 of the sample is lower or near the IC50 of the standard, the value will be useful, otherwise, it will be not.
Hope you got the aim of the work
initially calculate %inhibition and IC50 and use t-test for p-value calculation
Mann-Whitney U test to evaluate statistical difference between groups. Because you have three groups , you can try discriminant analisys-from Statistica 10 ( the line is:from Statistics-Multivariate exploratory techniques-Discriminant analisys).
@Jawla Bouaouda I wanted to know if in the end you did any statistical analysis and which one, since I want to do something similar, could you share the information and your data if you could? I'm new and I don't know much about statistics.
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