1. ArrayList Day 3
Be able to read AP Mult Choice questions tied to ArrayLists
Be able to write a program that uses ArrayLists that analyzes numbers.

2. Sample Question 2. Consider the following code segment.
ArrayList <Integer> list = new ArrayList<Integer> ();
list.add(new Integer(1));
list.add(new Integer(2));
list.add(new Integer(3));
list.set(2, new Integer(4));
list.add(2, new Integer(5));
list.add(new Integer(6));
System.out.println(list);
What is printed as a result of executing the code segment?
(A) [1, 2, 3, 4, 5]
(B) [1, 2, 4, 5, 6]
(C) [1, 2, 5, 4, 6]
(D) [1, 5, 2, 4, 6]
(E) [1, 5, 4, 3, 6]
Note: This will display the entire arraylist!!
Same as
System.out.println(list.toString());

3. 3. Consider the following data field and method.
private ArrayList nums;
// precondition: nums.size() > 0;
// nums contains Integer objects
public void numQuest() {
int k = 0;
Integer zero = new Integer(0);
while (k< nums.size())
if (nums.get(k).equals(zero))
nums.remove(k);
k++; }
Assume that ArrayList nums initially contains the following Integer values.
[0, 0, 4, 2, 5, 0, 3, 0]
What will ArrayList nums contain as a result of executing numQuest ?
(A) [0, 0, 4, 2, 5, 0, 3, 0]
(B) [4, 2, 5, 3]
(C) [0, 0, 0, 0, 4, 2, 5, 3]
(D) [3, 5, 2, 4, 0, 0, 0, 0]
(E) [0, 4, 2, 5, 3]

4. Program Input: 10 scores (integers) Output:
The high score
The low score
The average
The number of scores within 3 of the average
Push: Support an unknown number of scores
Push: Show the numbers in order low to high
Input: 10 scores and calculate the standard deviation

5. Standard Deviation Example.
Find the standard deviation of 4, 9, 11, 12, 17, 5, 8, 12, 14
First work out the mean (Average, xbar,…):
( )/9 =
Now, subtract the mean individually from each of the numbers in the question and square the result. This is equivalent to the (x - xbar)² step. x refers to the values in the question.
x               4        9        11       12       17       5       8       12      14 (x - xbar)²     38.7   1.49    0.60    3.16    45.9   27.3   4.94     14.3
Now add up these results (this is the 'sigma' in the formula):
139.55
Divide by n-1. n is the number of values, so in this case n-1 is 8:
/ 8 = 17.44
And finally, square root this:
4.18