Q:

ArrayList cannot find symbol Java

While coding for my school subject, I had to fill an arraylist with Doubles, until I got the message "in", in which case I could stop and scan two other values, so I could start my calculation. Because showing the whole code is irrelevant, I will just show the Class in which we have the problem:
    import java.util.Scanner;

class Test{
  double x1, x2;
  Scanner sc;
  ArrayList<Double> coefficients;

  void help() {    
    sc = new Scanner(System.in);
    coeffiecients = new ArrayList<Double>();

      while(!sc.next().equals("in")){
        coefficients.add(coefficient);
        coefficient = sc.nextDouble();
      }

      x1 = sc.nextDouble();
      x2 = sc.nextDouble();
    }

  public static void main(String[] args){
    new Test().help();
  }
}

So, with this code, I get the error message: cannot find symbol
symbol: variable nextDouble 
location: variable sc of type java.util.Scanner  
I just don't get why this code should give an error. Can someone help me?
[[Added my code, still got an error on ArrayList<Double> coefficients;
Why is that wrong?]]
The correct code is under here!
Changes are all described in answer no.1
import java.util.*;

class Test{
  double x1, x2;
  Scanner sc;
  ArrayList<Double> coefficients;
  double coefficient;

  void help() {    
    sc = new Scanner(System.in);
    coefficients = new ArrayList<Double>();

      while(!sc.next().equals("in")){
        coefficients.add(coefficient);
        coefficient = sc.nextDouble();
      }

      x1 = sc.nextDouble();
      x2 = sc.nextDouble();
    }

  public static void main(String[] args){
    new Test().help();
  }
}

A:

nextDouble is a Scanner method, not a field. You need to call the method
coefficient = sc.nextDouble();
x1 = sc.nextDouble();
x2 = sc.nextDouble();

