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Table 5 Sample sizes, mean thicknesses and standard deviations of tephra thickness at each of the sample sites. Confidence limits for the sample size assuming a 10 mm error in mean thickness is acceptable and the number of samples required to estimate the mean thickness with 95% confidence

From: Preservation of thin tephra

Location

n

\( \overline{\mathrm{x}} \)

δ

Confidence; 10 mm Error

n; 95% Confidence Interval

W Finisterres, PNG

148

49.1

36.5

99.9%

52

Crests

26

46.2

26.2

94.8%

27

Erosional slopes

58

38.1

36.2

96.5%

51

Depositional sites

64

60.2

37.7

96.6%

55

Non tussock; waterlogged

14

70.0

44.2

60.5%

76

Tussock; wet sites

53

56.0

39.8

93.3%

61

Shrublands; well-drained

81

40.9

30.5

99.7%

36

Ohanopecosh, WA

19

51.6

24.5

92.5%

24

Kodiak, AK

26

164.0

63.4

57.6%

155

Kodiak Site X7

24

160.4

61.8

57.1%

147