Which statistical test to use?

#1
Hi

I am trying to work out which statistical test can be used to establish if there is a significant difference between 12 tensile test sample results undertaken on one machine at 20 degrees Celsius, against 24 tensile test sample results undertaken on a second machine at 21 degrees Celsius.

I have recently been introduced to, and am vaguely familiar, with four types of statistical test ( T-test, Wilcoxon test, Mann-Whitney U test and Chi-Square test) and would like to use one of them, but I don't know which one.

Both sets of tests were conducted under 4 different environmental conditions:

1st machine @ 20 degrees C = (3 dry cord samples, 3 seawater soaked cord samples, 3 rainwater soaked cord samples and 3 tap water soaked cord samples)
2nd machine @ 21 degrees C = (6 dry cord samples, 6 seawater soaked cord samples, 6 rainwater soaked cord samples and 6 tap water soaked cord samples)

I was wondering which one of the four statistical tests mentioned above could cover that amount of 'jumbled up' results.

I look forward to any replies.

Tim