Tools for Quantitative Archaeology |
resampleBRED: Estimate Sampling Error for Brainderd-Robinson & Euclidean Distance Coefficients
resampleBRED provides a Monte Carlo estimate of the sampling error of the Brainerd Robinson coefficient and Euclidean Distance Coefficient (based on percents) of a sample drawn from a known population or of two samples drawn from the same population. Input consists of the population proportions (or counts) and the sample size or sample sizes to be drawn. Output consists of a table of probabilities of getting the same or lower BR coefficient (as or less similar) and the same or greater Euclidean Distance Coefficient between a sample of the specified size drawn from the population and the population itself or between two different samples drawn from the population. A histogram is also provided. This program replaces the BRSample program (it includes all of the functiona;lity of that program and adds computations for Euclidean Distance computations. The program was initially developed for Brainderd-Robinson Coefficients based on a suggestion from Warren DeBoer of Queens College and is described and used in DeBoer et al. (1996).
SAMPLE PROGRAM RUN
File or Device for Output (CON for Screen) {CON} ? Random Generator Seed (0 to set from clock) {0} ? Read Population Data from [K]eyboard or a [F]ile {K} ? Number of Types in the Population ? 4 Population Proportion (or % or Count) ? 12 Population Proportion (or % or Count) ? 31 Population Proportion (or % or Count) ? 64 Population Proportion (or % or Count) ? 133 Input Total = 240.00 [P]opulation-Sample or [S]ample-Sample Similarity {P} ? Sample Size {100} ? Number of Monte Carlo Trials {10000} ? 100% Population-Sample Similarity Sample Size=20 Trials=10000
BR Mean=173.47 BR Std= 12.00 ED Mean= 15.24 ED Std= 12.00
Rerun Using Same Population {Y} ? Rerun Using Different Population {N} ?
SAMPLE PROGRAM OUTPUT
Estimate Sampling Error for Brainder-Robinson and Euclidean Distance Coefficients (c) Keith W. Kintigh, Arizona State University, 2007 Monte-Carlo samples with specified sample sizes are drawn with replacement from a single population with given type proportions. The proportion of Monte Carlo trials with a similarity coefficient <= K or a distance coefficient >= K estimates the probability of obtaining by chance a value as or more extreme than K between the sample and the population, or between two samples. Thus, a cumulative probability of 0.350 associated with a similarity coefficient of 150 indicates that 35% of the time a similarity of 150 or less would be obtained by chance, suggesting no significant difference. Population Percents (4 Types): Type-Pct 1 - 5.00 2 - 12.92 3 - 26.67 4 - 55.42 Population-Sample Similarity Sample Size=100 Trials=10000 BR Mean=188.04 BR Std= 5.66 ED Mean= 7.05 ED Std= 5.66 B-R Probability Estimates Based on % of Trials - (B-R Coeff, Prob, Cum Prob) 199:0.005,1.000 198:0.007,0.996 197:0.024,0.989 196:0.023,0.965 195:0.059,0.942 194:0.039,0.884 193:0.081,0.844 192:0.049,0.763 191:0.103,0.714 190:0.049,0.611 189:0.103,0.562 188:0.033,0.459 187:0.098,0.426 186:0.024,0.328 185:0.072,0.304 184:0.018,0.232 183:0.061,0.214 182:0.011,0.153 181:0.047,0.142 180:0.005,0.095 179:0.033,0.090 178:0.003,0.057 177:0.021,0.054 176:0.001,0.033 175:0.013,0.032 174:0.001,0.019 173:0.008,0.018 172:0.000,0.010 171:0.004,0.010 170:0.000,0.006 169:0.003,0.006 168:0.000,0.003 167:0.002,0.003 166:0.000,0.001 165:0.001,0.001 164:0.000,0.000 163:0.000,0.000 162:0.000,0.000 161:0.000,0.000 E-D Probability Estimates Based on % of Trials - (E-D Coeff, Prob, Cum Prob) 1:0.013,0.000 2:0.039,0.013 3:0.082,0.052 4:0.106,0.134 5:0.129,0.240 6:0.126,0.369 7:0.111,0.496 8:0.102,0.607 9:0.072,0.709 10:0.063,0.781 11:0.049,0.844 12:0.036,0.893 13:0.024,0.929 14:0.018,0.953 15:0.011,0.971 16:0.007,0.981 17:0.004,0.988 18:0.003,0.992 19:0.002,0.995 20:0.001,0.997 21:0.001,0.999 22:0.000,0.999 23:0.000,0.999 24:0.000,1.000 25:0.000,1.000 B-R Num of Pct of Cumulative Coeff Trials Trials Percent Histogram (*=60 trials) 200-198 114 1.1 100.0- 98.9 |** 197-195 1051 10.5 98.9- 88.3 |****************** 194-192 1694 16.9 88.3- 71.4 |**************************** 191-189 2549 25.5 71.4- 45.9 |****************************************** 188-186 1555 15.6 45.9- 30.4 |************************** 185-183 1503 15.0 30.4- 15.3 |************************* 182-180 639 6.4 15.3- 9.0 |*********** 179-177 568 5.7 9.0- 3.3 |********* 176-174 149 1.5 3.3- 1.8 |** 173-171 119 1.2 1.8- 0.6 |** 170-168 30 0.3 0.6- 0.3 | 167-165 27 0.3 0.3- 0.0 | 164-162 0 0.0 0.0- 0.0 | 161-159 2 0.0 0.0- 0.0 | E-D Num of Pct of Cumulative Coeff Trials Trials Percent Histogram (*=56 trials) 0- 1 131 1.3 2.6- 1.3 |** 2- 3 1209 12.1 25.5- 13.4 |********************** 4- 5 2353 23.5 60.5- 36.9 |****************************************** 6- 7 2373 23.7 84.4- 60.7 |****************************************** 8- 9 1743 17.4 95.5- 78.1 |******************************* 10- 11 1121 11.2 100.5- 89.3 |******************** 12- 13 600 6.0 101.3- 95.3 |*********** 14- 15 282 2.8 100.9- 98.1 |***** 16- 17 109 1.1 100.3- 99.2 |** 18- 19 51 0.5 100.2- 99.7 |* 20- 21 22 0.2 100.2- 99.9 | 22- 23 4 0.0 100.0-100.0 | 24- 25 2 0.0 100.0-100.0 |
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Page Last Updated - 18-Jul-2007