How to get specific values in an array and output an average?

Assuming that each of the people that you listed for an example is on a separate line in the text file, adding a for loop to your current code and changing a few lines will solve this for you.

import java.util.Scanner;
import java.io.File;
import java.util.ArrayList;

public class test {

    public static void main(String[] args) {

        File myFile = new File("C:\\Users\\Byoma\\Downloads\\Assignment1.txt");

        try {

            Scanner myScanner = new Scanner(myFile);

            while (myScanner.hasNextLine()) {
                String line = myScanner.nextLine();

                String[] tokens = line.split(",");
                String name = tokens[0];
                double sum = 0; //Initialized a double to sum the values
                for (int i = 1; i < tokens.length; i++) {
                    sum += Double.parseDouble(tokens[i]); //Parse the values in the text document as doubles
                }
                double average = sum / (tokens.length - 1); //Get the average by dividing the sum by the number of values
                System.out.println("Name: " + name + ", Average: " + average);
            }

            myScanner.close();
        }

        catch (Exception e) {
            System.out.println("Error reading file: " + myFile.getAbsolutePath());
        }
    }
}

You iterate through the elements of the array starting with element 1 and accumulate them, then divide the total sum of the elements by the number of elements (note that I used int for the accumulated sum, but you can use floats or doubles if your input is not integer values, and that you don't strictly need the count variable):

public class MyClass {
    public static void main(String args[]) {
        String[] array = {"Name", "11", "5", "107"};
        int accumulated = 0; //this will hold the sum of all the numbers
        int count = 0; //we use this to keep track of how many numbers we have
        for (int i = 1; i < array.length; i++) {
            //add the numbers, we convert them to int since they are strings
            accumulated = accumulated + Integer.parseInt(array[i]); 
            count++;
        }  
        System.out.println("Total sum: "+accumulated);
        System.out.println("Number of elements: "+count);
        float average = accumulated/count;
        System.out.println("Average: "+average);
    }
}

Output:

Total sum: 123
Number of elements: 3
Average: 41.0