a schematic illustration in tabular format of the model for analyzing the results of the research survey for each of four cells a b c and d columns 202 204 206 and 208 respectively the number of respondents in the sample n a n b n c and n d u2014 for each four cells a b c and d respectively is shown in row 210 step 1 the observed perception shown in row 212 for users cells a and b and non users cells c and d of the advertised brand is calculated as follows u03c3 n a n b n c n d the observed no of respondents answering with a positive response n a n b n c and n d u2014 for each four cells a b c and d see fig1 respectively is shown in row 212 step 2 the proportion of respondents answering with a positive response p a p b p c and p d u2014 for each four cells a b c and d respectively is shown in row 214 where step 3 the expected perception shown in row 216 for persons who saw the advertisement are calculated based on the observed perception of persons who did not see the advertisement e b p b u00b7 n b in group b and e d p d u00b7 n d in group d thus the expected perceptions of persons who saw the advertisement are shown as e a p e u00b7 n a and e c p d u00b7 n c step 5 the percentage of change in the perception of the brand as a result of exposure to the advertising campaign shown in row 218 may then be calculated as follows reference is made to fig3 which is an.