40 lines
926 B
Java
40 lines
926 B
Java
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import java.util.LinkedList;
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public class StdDev {
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LinkedList<Double> nums;
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public StdDev() {
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nums = new LinkedList<Double>();
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}
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public static void main(String[] args) {
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double[] testData = {2,4,4,4,5,5,7,9};
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StdDev sd = new StdDev();
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for (double x : testData) {
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sd.newNum(x);
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System.out.println(sd.getSD());
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}
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}
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public void newNum(double num) {
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nums.add(num);
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}
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public double getAvg() {
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if (nums.isEmpty()) return 0;
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double ret = 0;
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double sum = 0;
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for (double num : nums) {
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sum += num;
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}
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return sum / nums.size();
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}
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public double getSD() {
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double sqDiffs = 0;
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double avg = getAvg();
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for (double num : nums) {
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sqDiffs += (num - avg) * (num - avg);
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}
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return Math.sqrt(sqDiffs / nums.size());
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}
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}
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