The mean GPA for the population of seniors at SUNY Oneonta is µ = 3.0. An investigator believes that senior psychology majors have a significantly higher GPA than the mean GPA of the population. The mean GPA of N = 25 senior psychology majors is M = 3.3 with a standard deviation of s = 0.5. Please test the investigator's prediction using α = .05. If there is a significant difference, calculate Cohen’s d and interpret the size of the effect.