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Grading Program--Need help, please!!!

Rose Evans
Ranch Hand

Joined: Oct 14, 2004
Posts: 195
Hentay,

Youre right!! I am going to pour over the code until I understand each and every single piece of it. I can understand a code like that much better than the examples in my book. This code is exactly what I need to model future programs.....codes I can truly understand!! I want to learn the language, you're right having someone post the entire code doesn't make me think like I should, but having THAT particular code now, I can understand what methods and classes are, and what they really do.
I think it will help me tremendously!!!

Thanks for your input. I greatly appreciate it. I appreciate everyone's help. Thanks so much!!


) ) ) )
Rose Evans
Ranch Hand

Joined: Oct 14, 2004
Posts: 195
Hentay,

Youre right!! I am going to pour over the code until I understand each and every single piece of it. I can understand a code like that much better than the examples in my book. This code is exactly what I need to model future programs.....codes I can truly understand!! I want to learn the language, you're right having someone post the entire code doesn't make me think like I should, but having THAT particular code now, I can understand what methods and classes are, and what they really do.
I think it will help me tremendously!!!

Thanks for your input. I greatly appreciate it. I appreciate everyone's help. Thanks so much!!
fred rosenberger
lowercase baba
Bartender

Joined: Oct 02, 2003
Posts: 11153
    
  16

originally posted by Rose:
Student name: Rose
First quiz score: 95
Second quiz score: 75
Midterm Exam score: 96
Final Exam score: 80
Final score: 106.50 (Does this look right?)
Grade: A


i'm gonna have to say no, this doesn't look right. Step back for a minute, and forget the Java stuff. look at all the test/quiz scores. the highest grade somebody got on any single test was a 96%. How could their FINAL grade be HIGHER?

let's just talk about the math...

Generally, what we think of as a final grade for a class is an average. The most common meaning of "average" is the mean-average, where you simply add all the values up, and divide by the number of entries. so, the mean-average of 8,10,4 and 13 is (8+10+4+13)/4 = 35/4 = 8.75

note that the mean is less than some, but more than other values in your original list. it is impossible for the mean to be smaller than the lowest, or greater than the highest value of your original list. In fact, it shouldn't even be equal to either of these extremes.

Now, you have a couple things different in your grading program - you will not just take the mean average, because the final is supposed to count for more than the mid-term, which counts more than the quizzes (which makes sense, since the final is a bigger test).

NOTE: it is implied from the directions that the quiz scores will be entered as a raw score from 0-10 (i assume this since the directions say "Do not forget to normalize the quiz scores, They should be coverted to percentages before they are averaged in"). it should be pretty easy to convert these to percentages.

now, assuming you have the 4 PERCENTAGES, how do you average them? well, you need to calculate a WEIGHTED mean average - some of the percentages will count more than others (they are a HEAVIER factor in the final score - so they are weighted more - get it? :-) )

if the two quiz score are supposed to count for a TOTAL of 25% of the final score, they are worth 12.5% each. The mid-term is worth 25% of the final score, and the final is 50%. These are the 'weights' attatched to each test.

ok, so now what do we do? there are a number of ways of doing this, but i think this is the easiest to understand...

multiply each test-percentage by it's 'weight'. using your example, i'll assume the test scores were

quiz 1 = 95%
quiz 2 = 75%
midterm = 96%
final = 80%

so:
quiz 1 score * weight = 95 * 12.5% = 11.875
quiz 2 score * weight = 75 * 12.5% = 9.375
midterm exam * weight = 96 * 25% = 24
final exam * weight = 80 * 50% = 40

add up the four values = 11.875 + 9.375 + 24 + 40 = 85.25.

this is the final score. Note that it is close to the final score - this makes sense since the final 'counts the most'...


There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
Rose Evans
Ranch Hand

Joined: Oct 14, 2004
Posts: 195
Fred,

You are one smart guy! I really need to sit down and take different approaches to my programming. I only hope that I can be as good as you one day! Thank you so much for your help. It is greatly appreciated!
 
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