我没有计算平均值的问题,但是我的标准偏差总是出现一些偏差。我很难过。 对于标准偏差,我使用for循环返回数组,填充用户提示值并从每个值中减去平均值,然后对其进行平方。然后还有一个循环将它们汇总在一起,除以值的数量,然后对其进行平方根。我错了什么?在java中计算平均值和标准偏差
import java.util.Scanner;
public class Assignment4
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.println("Please enter the number of items:"); // PROMPTS USER FOR # OF ITEMS
double size = scan.nextDouble();
double meanSum = 0;
double deviationSum = 0;
double array[] = new double [(int) size];
System.out.println("Please enter the items");
for (int i = 0; i < size; i++)
{
array[i]= scan.nextDouble();
}
for (int i = 0; i < size; i++)
{
meanSum += array[i];
}
double mean = ((meanSum/size));
System.out.println("The mean is: " + mean);
//STANDARD DEVIATION CALCULATION
for (int i = 0; i < size; i++)
{
array[i] = (Math.pow((array[i] - mean), 2));
}
for (int i = 0; i < size; i++)
{
deviationSum += array[i];
}
double variance = ((deviationSum/size));
double standardDeviation = Math.sqrt(variance);
System.out.println("The standard deviation is: " + standardDeviation);
}
}
'我发生了什么问题?'你在比较什么?它是否使用[Bessel's Corresction](https://en.wikipedia.org/wiki/Bessel%27s_correction)例如'n-1'?请参阅http://stats.stackexchange.com/questions/17890/what-is-the-difference-between-n-and-n-1-in-calculating-population-variance和http://stats.stackexchange.com。/questions/3931 /直观解释 - 用n-1除 - 计算标准差 – copeg
啊!除以n-1固定它。非常感谢! –