Your research group believes Illinois State University college students drink eight 12-ounce cans of Pepsi per week. After a detailed study involving a sample size of 500 students, you determine a mean consumption of 5.0 cans per week by students and a standard deviation of 0.5 cans. Calculate the study's z-score to determine if your hypothesis of eight cans per week is accurate. The z-score is [____]