ANOVA Tables using 4 methods
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 | ********************************************************************** *** Reproducing one-way ANOVA Tables *** Valentim R. Alferes (University of Coimbra, Portugal) *** valferes@fpce.uc.pt ** This syntax reproduces traditional one-way ANOVA Tables ** from summary statistics in published articles. ** You have four methods, depending on the available data. ********************************************************************** ** METHOD 1: Ns Means, and SDs. * Enter, row by row, N, Mean and Standard Deviation for the * groups or experimental treatments (in the example, you have * three treatments). DATA LIST LIST /n(F8.0) m(f8.2) sd(f8.2). BEGIN DATA 6 10,50 2,30 7 11,34 3,60 8 15,17 4,10 END DATA. COMPUTE iv=$CASENUM. LOOP id=1 TO n. XSAVE OUTFILE=XOUT1. END LOOP. EXECUTE. GET FILE=XOUT1. COMPUTE dv=m. COMPUTE k=SQR((sd**2*(N-1))/2). IF (id=1) dv=m+k. IF (id=2) dv=m-k. EXECUTE. SUMMARIZE/TABLES=dv BY iv/FORMAT=NOLIST TOTAL /TITLE='Case Summaries'/CELLS=COUNT MEAN STDDEV VAR. ONEWAY dv BY iv. ********************************************************************** ** METHOD 2: Ns Means, and Variances. * Enter, row by row, N, Mean and Variance for the * groups or experimental treatments (in the example, you have * three treatments). DATA LIST LIST /n(F8.0) m(f8.2) var(f8.2). BEGIN DATA 6 10,50 5,29 7 11,34 12,96 8 15,17 16,81 END DATA. COMPUTE iv=$CASENUM. LOOP id=1 TO n. XSAVE OUTFILE=XOUT1. END LOOP. EXECUTE. GET FILE=XOUT1. COMPUTE dv=m. COMPUTE k=SQR((var*(N-1))/2). IF (id=1) dv=m+k. IF (id=2) dv=m-k. EXECUTE. SUMMARIZE/TABLES=dv BY iv/FORMAT=NOLIST TOTAL /TITLE='Case Summaries'/CELLS=COUNT MEAN STDDEV VAR. ONEWAY dv BY iv. ********************************************************************** ** METHOD 3: Ns, Means, and MSError. * Enter, row by row, N and Mean for the groups or experimental * treatments (in the example, you have three treatments). DATA LIST LIST /n(F8.0) m(f8.0). BEGIN DATA 6 10,50 7 11,34 8 15,17 END DATA. * Enter Mean Square Error. COMPUTE mse = 12.32667. COMPUTE iv=$CASENUM. LOOP id=1 TO n. XSAVE OUTFILE=XOUT1. END LOOP. EXECUTE. GET FILE=XOUT1. COMPUTE dv=m. COMPUTE k=SQR((mse*(N-1))/2). IF (id=1) dv=m+k. IF (id=2) dv=m-k. EXECUTE. SUMMARIZE/TABLES=dv BY iv/FORMAT=NOLIST TOTAL /TITLE='Case Summaries'/CELLS=COUNT MEAN. ONEWAY dv BY iv. ********************************************************************** ** METHOD 4: Means, DFnum, DFden, and MSError. * Enter, row by row, the Mean for the groups or experimental * treatments (in the example, you have three treatments). DATA LIST LIST /m(f8.2). BEGIN DATA 10,50 11,34 15,17 END DATA. * Enter degrees of freedom for numerator (between groups df). COMPUTE dfnum=2. * Enter degrees of freedom for denominator (within groups * or MSError df). COMPUTE dfden=18. * Enter MSError. COMPUTE mse=12.32667. COMPUTE iv=$CASENUM. COMPUTE n_tot=dfnum+dfden+1. COMPUTE n_treat=dfnum+1. COMPUTE nxi=RND(n_tot/n_treat). EXECUTE. CREATE cum=CSUM(nxi). SORT CASES BY cum(D). IF ($CASENUM=1) nxi=nxi-(cum-n_tot). EXECUTE. SORT CASES BY iv(A). LOOP id=1 TO nxi. XSAVE OUTFILE=XOUT1. END LOOP. EXECUTE. GET FILE=XOUT1. COMPUTE dv=m. COMPUTE k=SQR((mse*(nxi-1))/2). IF (id=1) dv=m+K. IF (id=2) dv=m-K. EXECUTE. SUMMARIZE/TABLES=dv BY iv/FORMAT=NOLIST TOTAL /TITLE='Case Summaries'/CELLS=COUNT MEAN. ONEWAY dv BY iv. ********************************************************************** ** Note ** With Method 4 you don't know the Ns per treatment from the original ** source. If they are equal, you will get the exact ANOVA Table. Otherwise, ** as is the case in this example, you get only an approximation, ** because the syntax assumes that the Ns are equal in all treatments ** (if N_TOT/N_TREAT is an integer), or that they are equal in all ** treatments, except for the last one (if N_TOT/N_TREAT is not an integer). ** ** The syntax bellow exemplifies the case for equal Ns per treatment. ********************************************************************** ** The following syntax does the ANOVA on raw data from Kirk **(1995, p. 167, Table 5.2-I) and compares it with Methods 1 and 4. ** Analysis of raw data from Kirk (1995, p. 167, Table 5.2-I). DATA LIST FREE /IV(F8.0) DV(F8.0). BEGIN DATA 1 4 1 6 1 3 1 3 1 1 1 3 1 2 1 2 2 4 2 5 2 4 2 3 2 2 2 3 2 4 2 3 3 5 3 6 3 5 3 4 3 3 3 4 3 3 3 4 4 3 4 5 4 6 4 5 4 6 4 7 4 8 4 10 END DATA. ONEWAY dv BY iv/STATISTICS DESCRIPTIVES. ** METHOD 1: Ns Means, and SDs. * Enter, row by row, N, Mean and Standard Deviation for the * groups or experimental treatments (in the example, you have * three treatments). DATA LIST LIST /n(F8.0) m(f8.2) sd(f8.6). BEGIN DATA 8 3,00 1,511858 8 3,50 0,925820 8 4,25 1,035098 8 6,25 2,121320 END DATA. COMPUTE iv=$CASENUM. LOOP id=1 TO n. XSAVE OUTFILE=XOUT1. END LOOP. EXECUTE. GET FILE=XOUT1. COMPUTE dv=m. COMPUTE k=SQR((sd**2*(N-1))/2). IF (id=1) dv=m+k. IF (id=2) dv=m-k. EXECUTE. SUMMARIZE/TABLES=dv BY iv/FORMAT=NOLIST TOTAL /TITLE='Case Summaries'/CELLS=COUNT MEAN STDDEV VAR. ONEWAY dv BY iv. ** METHOD 4: Means, DFnum, DFden, and MSError. * Enter, row by row, the Mean for the groups or experimental * treatments (in the example, you have three treatments). DATA LIST LIST /m(f8.2). BEGIN DATA 3,00 3,50 4,25 6,25 END DATA. * Enter degrees of freedom for numerator (between groups df). COMPUTE dfnum=3. * Enter degrees of freedom for denominator (within groups * or MSError df). COMPUTE dfden=28. * Enter MSError. COMPUTE mse=2.178571. COMPUTE iv=$CASENUM. COMPUTE n_tot=dfnum+dfden+1. COMPUTE n_treat=dfnum+1. COMPUTE nxi=RND(n_tot/n_treat). EXECUTE. CREATE cum=CSUM(nxi). SORT CASES BY cum(D). IF ($CASENUM=1) nxi=nxi-(cum-n_tot). EXECUTE. SORT CASES BY iv(A). LOOP id=1 TO nxi. XSAVE OUTFILE=XOUT1. END LOOP. EXECUTE. GET FILE=XOUT1. COMPUTE dv=m. COMPUTE k=SQR((mse*(nxi-1))/2). IF (id=1) dv=m+K. IF (id=2) dv=m-K. EXECUTE. SUMMARIZE/TABLES=dv BY iv/FORMAT=NOLIST TOTAL /TITLE='Case Summaries'/CELLS=COUNT MEAN. ONEWAY dv BY iv. ********************************************************************** Kirk, R. E. (1995). Experimental design: Procedures for the behavioral sciences (3rd ed.). Pacific Grove, CA: Brooks/Cole. **********************************************************************. |