City University is eager to attract new students. One strategy the university has chosen to attract new students is to demonstrate to prospective students the happiness of its current students (operationally defined as how the
students rated their satisfaction with various services offered by the university on a scale of 1–10). The university officials designed a survey asking about student happiness and sent the survey via e-mail to 25 percent of City University students with equal distributions of students in each class (first-year students, sophomores, juniors, and seniors). They received responses from students in each class, and the responses are in the figure below.