Answer:
import java.util.Arrays; // The Array class allows for array operations
import java.util.Scanner; // The Scanner class allows for user's inputs
public class Statistics {
public static void main(String[] args) {
// create an object of the Scanner class
Scanner input = new Scanner(System.in);
System.out.println("Please enter the number of students");
// Using "input" which is an object of the Scanner class,
// get the number of students.
int noOfStudents = input.nextInt();
// Create an array of scores whose length is equal to the number of students
// Array is of type double as students' scores could be floating point numbers
double[] scores = new double[noOfStudents];
// Create a loop that cycles as many times as the number of students.
// Each loops asks the user to enter the score of each student
// Initialize the scores array with each score at every loop
int i = 0; // This is a counter for the loop
while (i < noOfStudents) {
System.out.println("Enter score for student " + (i + 1));
scores[i] = input.nextDouble();
i++; // increment counter at every loop
}
// At the end of the loop above, the scores array should be completely
// initialized
// You might want to print out the scores before sorting
System.out.println(Arrays.toString(scores));
// Sort the scores array so as to be able to calculate the median
Arrays.sort(scores);
// Print out the results by calling the necessary methods
System.out.println("Mean score : " + mean(scores));
System.out.println("Median score is : " + median(scores));
System.out.println("Highest score : " + highest(scores));
System.out.println("Lowest score : " + lowest(scores));
}
// Method to calculate the mean of the scores in the scores array
// Initialize a variable, sum, to zero to allow for cumulative addition of the
// array elements.
// Loop through the scores array adding up the array elements cumulatively
// Divide the result of the sum by the length of the array to get the
// mean(average).
// In this case, scores array is represented by arr
public static double mean(double[] arr) {
double sum = 0;
for (int i = 0; i < arr.length; i++) {
sum += arr[i];
}
return sum / arr.length; // Return the mean (average).
} // End of the mean method
// Method to calculate the median of the scores in the scores array
// Median is the middle element in a sorted set of elements
// If the length(number of elements) of the sorted set of elements is even
// there will be two elements representing the median.
// To break this tie, the average of the two elements is found.
// In this case, scores array is represented by arr
public static double median(double[] arr) {
//Check if the length of the array is even or not.
//This will help to break the tie if it occurs.
if (arr.length % 2 != 0) {
int mid = (arr.length + 1) / 2; //mid represents the middle number
return arr[mid - 1]; // Because arrays are indexed from zero(0), 1 is subtracted from mid
} else {
int mid = (arr.length) / 2;
return (arr[mid] + arr[mid + 1]) / 2.0;
}
} // End of the method median
// Method to calculate the highest of the scores in the scores array
// In this case, the scores array is represented by arr
public static double highest(double[] arr) {
//Declare and initialize a temp variable to hold the first element in the array
double temp = arr[0];
//Loop through the array starting at the second position since the value in the first position has been stored in a temp variable
for (int i = 1; i < arr.length; i++) {
//At every loop, check if there is a number greater than the one stored in the temp variable
//If there is, replace temp with such number
if (arr[i] > temp) {
temp = arr[i];
}
}
return temp; //Return the highest number
} // End of the method highest
// Method to calculate the lowest of the scores in the scores array
// In this case the scores array is represented by arr
public static double lowest(double[] arr) {
//Declare and initialize a temp variable to hold the first element in the array
double temp = arr[0];
//Loop through the array starting at the second position since the value in the first position has been stored in a temp variable
for (int i = 1; i < arr.length; i++) {
//At every loop, check if there is a number less than the one stored in the temp variable
//If there is, replace temp with such number
if (arr[i] < temp) {
temp = arr[i];
}
}
return temp; //Return the lowest number
} // End of the method lowest
}
Explanation:
Explanations are explicitly written in the answer above in comments.
The source code file (Statistics.java) has been attached to this answer.
Hope this helps!.
