delegate all the different computation to methods of a class

called StatisticsProb, to make it actually be object oriented.
Right now, there are just prototypes of the methods.
method to get the number of values to be entered
get the number of values
compute the sum and the mean
compute the median
compute mode using a Map/Hashmap. plus some formatting
compute the standard deviation
compute 95% confidence interval margin.
clean up the main code to use the methods previously created
no idea why I made all these methods void, changing to return double
fixing some compile errors, commenting out prompts