The following class StatCalc defines a series of methods for computing statistics for a group of numbers.
/*
* An object of class StatCalc can be used to compute several simple statistics
* for a set of numbers. Numbers are entered into the dataset using
* the enter(double) method. Methods are provided to return the following
* statistics for the set of numbers that have been entered: The number
* of items, the sum of the items, the average, and the standard deviation
*/
public class StatCalc {
private int count; // Number of numbers that have been entered.
private double sum; // The sum of all the items that have been entered.
private double squareSum; // The sum of the squares of all the items.
/**
* Add a number to the dataset. The statistics will be computed for all
* the numbers that have been added to the dataset using this method.
*/
public void enter(double num) {
count++;
sum += num;
squareSum += num*num;
}
/**
* Return the number of items that have been entered into the dataset.
*/
public int getCount() {
return count;
}
/**
* Return the sum of all the numbers that have been entered.
*/
public double getSum() {
return sum;
}
/**
* Return the average of all the items that have been entered.
* The return value is Double.NaN if no numbers have been entered.
*/
public double getMean() {
return sum / count;
}
/**
* Return the standard deviation of all the items that have been entered.
* The return value is Double.NaN if no numbers have been entered.
*/
public double getStandardDeviation() {
double mean = getMean();
return Math.sqrt( squareSum/count mean*mean );
}
} // end class StatCalc
Using the StatCalc class, write a program that calculates and then displays as output to the console, the following statistics against the set of numbers given below.
Statistics that must be calculated:
Count Quantity of numbers in the data set.Mean The mean or average of the numbers in the data set.Standard Deviation The measure of variance (or dispersion) from the mean.The set of numbers that you must use is as follows:
5 7 12 23 3 2 8 14 10 5 9 13
You must create a program with a main method that defines the StatCalc class and instantiates an instance of StatCalc called myStatCalc. Your program should instantiate the instance of the StatCalc using a statement similar to the following:
StatCalc myStatCalc;
myStatCalc = new StatCalc();
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