©Dawn Iacobucci, p.1 FYI: One-Way Chi-Square Eqn:df=I-1 Why/When? e.g., compare sample to population characteristics, or to previous study’s benchmark

©Dawn Iacobucci, p.2 One-Way Chi-Square: Example Example:< your data: o i ’s: n=50 (pop proportions:20%24%30%26%) benchmark: e i ’s: X 2 = [(5-10) 2 /10] +[(10-12) 2 /12] +[(20-15) 2 /15] +[(15-13) 2 /13 = = (critical value on 3 df=7.82)

©Dawn Iacobucci, p.3 The Case of the Blue M&M’s PLAINPEANUT e i ’so i ’se i ’so i ’s blue brown green orange red yellow critical chi-square on 5 df = 11.07

©Dawn Iacobucci, p.4 The Case of the Blue M&M’s: Does aggregating help? PLAINPEANUT e i ’so i ’se i ’so i ’s blue brown green orange red yellow