# Thread: Which statistical test shoud I use?

1. ## Which statistical test shoud I use?

I have concentrations of one metal in two organs of a snail – kidney and foot (n=10). What statistical test should I use to check if the difference is significant between them?

2. ## Re: Which statistical test shoud I use?

Are the data paired or independent? If you had 10 snails, and had paired kidney and foot data for each snail, use a paired t-test. If the data are independent use a 2-sample t-test. If the data are not normal, there are non-parametric equivalents to these.

This assumes that you meant differences between organs. If you meant differences between snails, that is a different question.

3. ## Re: Which statistical test shoud I use?

Thank you. Yes, I meant differences between organs. My data is non-parametric.

4. ## Re: Which statistical test shoud I use?

How do you know that it is non-parametric? Does it fail a normality test? If the data are paired, test the differences for normality, not the groups.

5. ## Re: Which statistical test shoud I use?

Shapiro Wilk Sig. was smaller than 0,05; so my data is non-parametric. Am I wrong? I have serious problems with my data analysis. ;/

6. ## Re: Which statistical test shoud I use?

If your data are paired (you still haven't stated) calculate the differences and use the 1-sample Wilcoxon test. If not paired, use Mann-Whitney test.

7. ## Re: Which statistical test shoud I use?

In the first post there seems to be four factors (or five) and a mixed model because of within individual (foot kidney) effects and between individual effects.

I guess that the amount of metal will have many values close to zero and a few larger, so that it is a skewed distribution. Taking logs could possibly solve that.

8. ## Re: Which statistical test shoud I use?

I didn't see that thread. That description is completely different from the one in this thread.

 Tweet

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts