The manager of a video store was interested in examining the relationship between a person's weekly take-home pay and the number of movies rented by that person per week. He polled 50 customers. In an Excel spreadsheet, the take-home pays of the 50 customers are stored in cells A1 to A50, and the number of videos rented per week by the 50 customers are stored in cells B1 to B50. Write an Excel formula that will find the correlation coefficient of this data.