Simple Math Python Script

To create a python program to ask the user to enter the mean and variance of the distribution. Python script needs to be able to allow user to enter any value between minus infinity and plus infinity, but the variance must be a value input larger than 0. Need to integrate certain control mechanism to ensure that the variance condition is fulfilled and the user input is NUMERIC not character.

Ensure that if USER press ENTER on the textbox without any value, the program will automatically set the population mean = 0 and variance of population = 1