Table 2 Student’s t-test (top/right) and Mann–Whitney U test (bottom/left) p-value results for bulk δ13C from ancient and modern Phragmites.

From: Ancient Great Wall building materials reveal environmental changes associated with oases in northwestern China

δ13C*

Han (n = 26)

Jin (n = 5)

Tang (n = 8)

Song (n = 3)

Mod. East (n = 7)

Mod. West (n = 5)

Mod. all (n = 12)

Han (− 23.7‰)

–

0.016

0.273

0.398

1.000

0.002

0.048

Jin (− 24.5‰)

0.011

–

0.164

0.990

0.075

 < 0.001

0.002

Tang (− 24.0‰)

0.207

0.222

–

0.595

0.472

 < 0.001

0.018

Song (− 24.5‰)

0.209

0.571

0.376

–

0.399

0.035

0.135

Mod. East (− 23.7‰)

0.877

0.106

0.536

0.267

–

0.001

n/a

Mod. West (− 21.7‰)

0.001

0.008

0.002

0.036

0.003

–

n/a

Mod. all (− 22.9‰)

0.057

0.014

0.047

0.070

n/a

n/a

–

  1.  *Mean reported as ‰ vs. VPDB.
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