find a zscore in javascript

To find the z-score of a data point in an array using JavaScript, you can follow these steps:

1. Calculate the mean (average) of the array.
2. Calculate the standard deviation of the array.
3. Calculate the distance between the data point and the mean by subtracting the mean from the data point.
4. Divide the distance by the standard deviation to get the z-score.

Here's the code for finding the z-score of a data point in an array:

index.tsx
function zScore(arr, x) {
  // Calculate the mean of the array
  const mean = arr.reduce((a, b) => a + b, 0) / arr.length;

  // Calculate the standard deviation of the array
  const variance = arr.reduce((a, b) => a + Math.pow(b - mean, 2), 0) / arr.length;
  const stdDev = Math.sqrt(variance);

  // Calculate the z-score of the data point
  const distance = x - mean;
  const zScore = distance / stdDev;

  return zScore;
}

// Example usage
const data = [1, 2, 3, 4, 5];
const dataPoint = 3;
const z = zScore(data, dataPoint);
console.log(z); // Output: 0
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In this example, we have an array of data data and a data point dataPoint. We're using the zScore function to find the z-score of the data point in the array. The output of the function in this case is 0, which means the data point is exactly at the mean of the array.