stats.m

matlab宝典,电子工业出版社,包含该书的源码4-6章

% Script file stats.m
%
% Purpose:
%   To calculate mean and the standard deviation of
% an input data set containing and arbitrary number
% of input values.
%
% Define variables:
%  n       The number of input samples
% std_dev   The standard devation of the input samples
% sum1     The sum of the input values
% sum2     The sum of the squares of the input values
% x        input data value
% xvar     The average of the input samples
% Initalize variables
n=0;sum1=0;sum2=0;
%Read the input values
x=input('Enter the first value: ');

%创建求解数组元素和的循环结构
while x>=0
    n=n+1;
    sum1=sum1+x;
    sum2=sum2+x^2;
    
    % 读入原始数据
    x=input('Enter next value: ');
end
%计算平均值和标准方差
xvar=sum1/n;
std_dev=sqrt((n*sum2-sum1^2)/(n*(n-1)));
%在命令窗口显示结果
fprintf('The mean of this data set is: %f\n',xvar);
fprintf('The standard deviation is: %f\n',std_dev);
fprintf('The number of data is: %d\n',n);