How to test for differences in mean values within a population

#1
Hello,

I am stuck on what seems to be a very simple question. I recorded the duration of 20 bird songs and I want to know whether the average duration is significantly shorter or longer for bird(s). Is there any way to test for normality?

BIRD_ID DURATION
A01 0.03
A02 0.10
A11 0.06
A14 0.07
B12 0.11
...
 

Karabiner

TS Contributor
#2
I want to know whether the average duration is significantly shorter or longer for bird(s)
I find it hard to understand what your question is. You want to know whether the average duration is longer or shorter than....what? And what do you mean by "bird(s)"? One bird? All birds? What is possibly meant by the "average duration of one bird", then?

With kind regards

Karabiner