Statistical Class Define a class that can accumulate information about a sequence of numbers and calculate its average and Standard Deviation (STD). class Statistic { public: //Constructor: initialize private data Statistic(); /f/ add an item to the statistics void add(double x); // get average double average() const; // get Standard deviation: using the hint double STD() con5#; private: // private member data }3 For testing purposes, use the class to calculate the average and Standard Deviation of the sequence of number that you submitted to the first discussion. The class should be usable by any code that needs to accumulate statistics on a sequence of values. You never know when that need will arise. Perhaps sooner than you think! _Hint: STD(X) = square root of { (2 x2-(2x * Ex: / N))/(N-1)}