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• <br />Bob Liddle -3- 1~larch 13; 1981 <br />Vegetation Baseline Information Appendix H, 2H 2.04.10 <br />1. None of the figures 3.1-1, 3.2.1-1, 3.2.2-1, 3.2.3-1, 3.2.4-1 is present in <br />Appendix - H. These should be provided. <br />2. Why was the reference area for mountain - shrubland (dry phase) selected <br />after analysis of the affected area for only one parameter (cover)? <br />3. Snowmass' formula for the students t-test is inappropriate. Sokal and Rolhf <br />(1969) state that when sample sizes are unequal but large enough so that lnl - <br />(nl - 1) is a very small value the formula Snowmass has presented becomes <br />adequate representation. Snowmass needs to reevaluate their statistical <br />comparisons utilizing a formula such as (Zar, 1974): <br />t = X i~x~ <br />S_ _ <br />X1 x2 <br />where Sx x S2 + S2 <br />1 - 2 <br />nl n2 <br />and nl -sample size for sample 1 <br />n2 -sample size for sample 2 <br />S12 - variance for sample 1 <br />S22 - variance for sample 2 <br />X - mean value for sample 1 <br />1 <br />x - mean value for sample 2 <br />2 <br />(n - 1)S 2 <br />and S~ _ - 1 1 <br />p (nl - 1) + <br />+ (n2 - 1) S2 <br />(n2 - 1) <br />5. The sample adequacy formula presented by Snowmass is inappropriate in the <br />event that comparisons are to be made between reference and affected areas. <br />The formula should be; <br />~~min 2 Z2S2 <br />(d X)2 <br />In addition, Snov~mass should utilize the z value for a two-tailed test at the <br />80% confidence level (1.282) in the case of woody vegetative communities (1.646, <br />in the case of herbaceous communities). <br />6. Snowmass needs to discuss the appropriateness of selecting "nearest" individuals <br />rather than plotting an additional transect relative to their sampling methodology. <br />7. Snowmass needs to discuss the appropriateness of using proporation of cover ni/N <br />in the Shannon - Wiener information statistic rather than the commonly accepted <br />proportion of the total number of individuals occurring in species i <br />