Title: Array Defining Features Matrix

Author: Kate Deibel

Date: March 30, 2004

Technique: Defining Features Matrix

Before Class Preparation Time: MEDIUM

Class Completion Time: LOW

In-Class Analysis Time: LOW

Out-Of-Class Analysis Time: LOW

Assessment Goals:
Topics:
Purpose:

This CAT allows instructors to find out if students understand the similarities and differences between an array of integers and an integer variable.


Activity:

Fill out the following matrix. This matrix lists some conjectures and it's your job to decide if these hold under two conditions. The first condition is that of an integer variable and the second is that of an array of integers. Please complete the table with '+' or '-' labels.


Conjecture Integer variable (named rainfall) An array of integers (named rainfall)
Holds data    
Holds multiple values simultaneously    
Can use = to assign to another variable    
When used as a parameter, it is passed using the call by value convention    
rainfall[0] is syntactically valid    
Can compare to another variable using ==    
rainfall = {1,2,3,4,5} is legal    

Solution:
Conjecture Integer variable (named rainfall) An array of integers (named rainfall)
Holds data + +
Holds multiple values simultaneously - +
Can use = to assign to another variable + -
When used as a parameter, it is passed using the call by value convention + -
rainfall[0] is syntactically valid - +
Can compare to another variable using == - +
rainfall = {1,2,3,4,5} is legal - - (this is tricky since this isn't a declaration of the array; this is not valid notation in an assignment statement)

Instructor Responses: Response Analysis:

The following must be done out of class:

  1. In a first pass, mark and count the number of incorrect answers. Also, mark any answers that you find surprising.
  2. For each question that has a significant (your judgement call) of incorrect answers, do the following:
    1. Look through the answers to these questions.
    2. Attempt to identify the nature of the most common errors that are made.
  3. Discuss these errors in class, using the common mistakes that you identified.

In-class feedback can be done by having students write or say out loud their own answers, but caution must be taken to avoid embarassing or ridiculing a student for making mistakes.



Variant Uses of Activity:
Device-Enabled: Has Been Enabled

Related Topics: