The statement that is NOT true is: "The mean of X is less than the mean of Y."
In this scenario, X represents the number of loans closed, and Y represents the amount of money made by a loan agent. The mean of X is the average number of loans closed, while the mean of Y is the average amount of money made. Since each loan closed contributes $50 to the daily salary, the mean of Y is directly influenced by the mean of X. Therefore, the mean of Y will be greater than the mean of X, making the statement false.
The other statements about the standard deviation and shape of the probability distribution of Y are accurate in the context of the given information.