Quote:
Originally Posted by wyndslash
i know they're not the same...but i think we just can't understand each other. or i'm too confused x.x
well, i did ask my math prof and he told me i could just add each component, get the average and multiply it by the weight of each component. but it seems you disagree, so i really want to understand your explanation.
actually, i only used one quiz as an example, but there will be more quizzes, and each quiz is simply broken down as follows:
part 1 - 30%
part 2 - 10%
each part can have different denominators depending on the total number of items in the quiz. though it's easier if they all have the same total number of items.
the example i used had a total number of 30 items for the first part, and 20 total items for the second part, but it could also be the other way around.
i think what is different is that i took each component as itself, and you took it as part of the 50 total number of items.
in the bigger picture, it could be like this: (let's assume all quizzes have 50 total number of items)
quiz 1: part 1 - 20/30; part 2 - 15/20
quiz 2: part 1 - 30/30; part 2 - 20/20
quiz 3: part 1 - 25/30, part 2 - 10/20
so what i want to know is, can i separate each component, add them all up and multiply them by their weight? it would look like this:
part 1 - ((75/90)x100)x 0.3 = 24.99%
part 2 - ((45/60)x100)x 0.1 = 7.5%
total - 32.49% of the 40% for quizzes
|
The problem we are having here is that the marks for the two separate parts do not have the same value.
You say that part 1 is worth 30% and part 2 is worth 10%.
So part one is worth three times part 2.
But you also say that part 1 has 30 marks, and part 2 has 20 marks. The only way that both statements could be true is if a mark in part 1 is worth twice what a mark in part 2 is worth.
However, that seem irrelevant to your last calculation, since you are keeping the part 1 and part 2 marks separate.
Yes, you can add up the marks for all the part 1s and get that percentage, and all the marks for the part 2s and get that percentage, and then just add the two percentages together. But you can also just do the same with the individual numbers.
quiz 1: part 1 - 20/30; part 2 - 15/20
quiz 2: part 1 - 30/30; part 2 - 20/20
quiz 3: part 1 - 25/30, part 2 - 10/20
part 1s:
20/30*.1*100 = 6.7%
30/30*.1*100 = 10%
25/30*.1*100 = 8.3%
part 2s
15/20*.033*100 = 2.5%
20/20*.033*100 = 3.3%
10/20*.033*100 = 1.7%
Total = 32.5% (the recurring decimals add up nicely to give an exact result)