does posting calorie content for menu items affect people's choices in fast food restaurants? according to results obtained by elbel, gyamfi, and kersh (2011), the answer is no. the researchers monitored the calorie content of food purchases for children and adolescents in four large fast food chains before and after mandatory labeling began in new york city. although most adolescents reported noticing the calorie labels, apparently the labels had no effect on their choices. a researcher decides to replicate this study in the twin cities by showing one sample of children and adolescents a menu without calorie content and another sample a menu with calorie content. what test should you use to determine whether knowing the calorie content influences the mean number of calories of food purchased by children and adolescents?