Question

我尝试使用javascript制作均值偏差计算器但是当我尝试输出|x-x̅|的总和时，它总是返回0;

＆＃13;

var frequencies = []
var output = document.getElementById("text")

function add() {
  var score = document.getElementById("lol").value
  frequencies.push(score)

}

function show() {
  //Calculate the mean
  var total = 0
  var mean = 0
  var scoreMinusMean = []
  var summation = 0
  for (i = 0; i < frequencies.length; i++) {
    total += parseInt(frequencies[i])
  }
  mean = total / frequencies.length
  //Gets the score - mean
  for (j = 0; j < frequencies.length; j++) {
    scoreMinusMean.push(Math.abs(frequencies[j] - mean))
  }
  for (k = 0; k < scoreMinusMean; k++) {
    summation += scoreMinusMean[k]
  }
  output.innerHTML = scoreMinusMean
}

＆＃13;

<input id="lol">
<button onclick="add()">Add</button>
<button onclick="show()">Show</button>

Output: <span id="text"></span>

＆＃13;

Answer 1

在您的上一个循环中，您所拥有的条件为k < scoreMinusMean，您忘记在其中添加.length。它应该是

for (k = 0; k < scoreMinusMean.length; k++) {  
    summation += scoreMinusMean[k]
}

此外，您应该在声明变量之前使用let，否则它们将变为全局变量。

＆＃13;

var frequencies = [];
var output = document.getElementById("text")

function add() {
  var score = document.getElementById("lol").value
  frequencies.push(score)

}

function show() {
  //Calculate the mean
  var total = 0
  var mean = 0
  var scoreMinusMean = []
  var summation = 0
  for (i = 0; i < frequencies.length; i++) {
    total += parseInt(frequencies[i])
  }
  mean = total / frequencies.length
  //Gets the score - mean
  for (j = 0; j < frequencies.length; j++) {
    scoreMinusMean.push(Math.abs(frequencies[j] - mean))
  }
  for (k = 0; k < scoreMinusMean.length; k++) {  
    summation += scoreMinusMean[k]
  }
  output.innerHTML = summation
}

＆＃13;

<input id="lol">
<button onclick="add()">Add</button>
<button onclick="show()">Show</button>

Output: <span id="text"></span>

＆＃13;

Answer 2

您的代码的最后四行应该是：

 for (k = 0; k < scoreMinusMean.length; k++) {
    summation += scoreMinusMean[k]
  }
  output.innerHTML =summation/frequencies.length
}

当你忘记了阵列上的.length和标准偏差时，你需要再次平均偏差（即除以平均偏差的总和，除以元素的数量）。

得分总和 - 均值不起作用

2 个答案: