```
I have to write a program in java to compute the standard deviation and the mean. I am also to write a test program that will prompt the user to enter 10 numbers and display the mean and standard deviation. I have stared on the program and so far this is all I have
import java.util.Scanner;
public class Statistics {
//declaring creating array of 10
double[] list = new double[10];
//Scanner for input
Scanner input = new Scanner(System.in); {
for (int i = 0; i < 1; i++) {
System.out.print("Enter 10 numbers: ");
list[i] = input.nextDouble();
//Print
System.out.println("The mean is " + mean(list));
System.out.println("The standard deviation is " + deviation(list));
}
}
/** Method that compute the deviation of double values */
public static double deviation (double[] x) {
double mean = mean(x);
double squareSum = 0;
for(int i = 0; i < x.length; i++) {
squareSum += Math.pow(x[i]-mean, 2);
}
return Math.sqrt(squareSum) / (x.length - 1);
}
/** Method that compute the mean of double values */
public static double mean(double[] x) {
double sum = 0;
for (int i = 0; i < x.length; i++)
sum+= x[i];
return sum /x.length;
}
//printing the array
public static void printArray(double[] x) {
for (int i = 0; i < x.length; i++) {
System.out.println(x[i] + " ");
System.out.println();
}
}
}
above is the prompt and the mean and standard deviation formula
the test program is below.
public class TestStatics {
/**
* Test the statistics methods for Assignment #1.
* @param args
*/
public static void main(String[] args) {
// how much of a difference between expected and computed
// will be allowed.
double tolerance = 1e-10;
// first, test on an array of mixed numbers
double[] tans = genData1();
double expectedMean = 0.05848465036; // 0.05848465036620792;
double computedMean = Statistics.mean(tans);
double diffMean = Math.abs(expectedMean-computedMean);
System.out.println("The computed mean is " + computedMean +
" and the expected mean is " + expectedMean +
" for a difference of " + diffMean
);
if(diffMean > tolerance) {
System.out.println("Test of mean on genData1 failed");
} else {
System.out.println("Test of mean on genData1 passed");
}
double expectedDeviation = 18.47695685606; // 18.47695685606356
double computedeDeviation = Statistics.deviation(tans);
double diffDeviation = Math.abs(expectedDeviation-computedeDeviation);
System.out.println("The computed deviation is " + computedeDeviation +
" and the expected deviation is " + expectedDeviation +
" for a difference of " + diffDeviation
);
if(diffDeviation > tolerance) {
System.out.println("Test of deviation on genData1 failed");
} else {
System.out.println("Test of deviation on genData1 passed");
}
// now test on an empty array
double [] noData = new double[0];
computedMean = Statistics.mean(noData);
if(!Double.isNaN(computedMean)) {
System.out.println("Test of mean on empty array failed");
} else {
System.out.println("Test of mean on empty array passed");
}
expectedDeviation = 0;
computedeDeviation = Statistics.deviation(noData);
diffDeviation = Math.abs(expectedDeviation-computedeDeviation);
System.out.println("The computed deviation is " + computedeDeviation +
" and the expected deviation is " + expectedDeviation +
" for a difference of " + diffDeviation
);
if(diffDeviation > tolerance) {
System.out.println("Test of deviation on empty array failed");
} else {
System.out.println("Test of deviation on empty array passed");
}
/*
* Comment:
* In the case of the deviation, the running total ends up as 0 and
* that is divided by -1.
*/
}
private static double[] genData1() {
int start = 1234;
int end = 2345;
double[] data = new double[end-start];
for(int i = start; i < end; i++ ) {
data[i-start] = Math.tan(i);
}
return data;
}
}
when i run my program it just gives me the information in the test program but never allows me to input 10 number to check it against. can you please help me. I am sorry if i am all over the place. I am fairly new to java.
Thanks in advance for your help.
```

## Recommended Answers

Jump to PostCan you edit the code and give it proper indentations and formatting? Nested statements should be indented 3-4 spaces and should not all start in the first column. Proper formatting makes it a lot easier to read and understand code.

the test program but never allows me to input …

Jump to Postthe test program i can't touch.

What is the code that is posted? What part of it can you change? Why isn't the code properly formatted? Please format the part of the code that you are allowed to change.

WHat happens when you execute the code? How many …

Jump to PostYou left off the console contents from when you execute the program so I can see what it does when you execute it.

Jump to PostIn your test program, try instantiating the statistics class like so:

Statistics stats = new Statistics();

Then you can refer to the methods using 'stats.xxx'

Jump to PostPlease post the console from when you execute the program that shows what command you entered to execute the program, that shows what the program printed on the screen and that shows what you typed in. I don't know how you are executing the program. I don't know what command …

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