Unutterably Silly So what are you doing RIGHT NOW?

[bjones6416]

I just made a shoofly pie, just because I had never tasted one and it seemed like the thing to do. I've been a baking fool lately, and not even because I want to eat any of it. I just want to bake. This is definitely a strange phase of my life.

[wyndslash]

i have a question (since math easily stumps me, lol). let's say in a grading system, quizzes make up 40% of the grade. would you get a different score in the quizzes if the 40% was further broken down into, let's say, 30% for solving and 10% for explanation?

would this be a correct way to solve for it? let's say, one quiz is for 50 pts, so if you go by the first method and you get 40/50, then you get 32% of the 40%.

but if going by the second method of a further breakdown (same final score of 40/50):
let's say that for part I (solving), it's over 30, and you get 30/30
for part 2 (explanation), it's over 20, and you get 10/20

since part 1 is 30% and you got perfect there, you already get 30%
part 2 is 10% and you got 10/20, you get 5%

so that's a total of 35%, as compared to 32% if we go by the first method.

does that make any sense? i'm rather confused, lol.

[pdurrant]

Originally Posted by wyndslash

i have a question (since math easily stumps me, lol). let's say in a grading system, quizzes make up 40% of the grade. would you get a different score in the quizzes if the 40% was further broken down into, let's say, 30% for solving and 10% for explanation?

would this be a correct way to solve for it? let's say, one quiz is for 50 pts, so if you go by the first method and you get 40/50, then you get 32% of the 40%.

but if going by the second method of a further breakdown (same final score of 40/50):
let's say that for part I (solving), it's over 30, and you get 30/30
for part 2 (explanation), it's over 20, and you get 10/20

since part 1 is 30% and you got perfect there, you already get 30%
part 2 is 10% and you got 10/20, you get 5%

so that's a total of 35%, as compared to 32% if we go by the first method.

does that make any sense? i'm rather confused, lol.

Your error is in calculating that part 1 is worth 30% of the final mark and part 2 is 10% of the final mark. That's wrong. You're calculating the proportion based on the 40 marks you scored. You need to calculate it based on the 50 marks that are available.

Part 1 is worth 3/5 of 40%, or 24% of the final mark
Part 2 is worth 2/5 of 40% or 16% of the final mark.

You got part 1 completely right, and that's worth 24%
You got part 2 half right, so that's worth 8%.

Total: 32%, as expected.


[EDIT:

Re-reading, I see you actually made a different, but similar error.

You assert that part 1 is 30% and part 2 10%. But you then make a mistake in calculating the number of marks that would be available for part 1 and part 2. For part 1 to be worth 30% of the final marks, it would need to have 50/40*30 marks = 37.5 marks, and part 2 would have 12.5 marks.

By getting part one completely right you'd get 30%, but in part 2 you'd only have got 2.5 marks out of 12.5 marks. that's 1/5th of the 10% available for that section: 2%.

The total is still 32% of the final marks.]

[wyndslash]

i think i'm more confused now than ever x.x

[pdurrant]

Originally Posted by wyndslash

i think i'm more confused now than ever x.x

OK, let me highlight where you made your mistake.

Originally Posted by wyndslash

[snip]let's say in a grading system, quizzes make up 40% of the grade.[snip]

[snip] one quiz is for 50 pts, [snip] you get 40/50, then you get 32% of the 40%.

This is all correct.

Originally Posted by wyndslash

[snip]a further breakdown (same final score of 40/50):
let's say that for part I (solving), it's over 30, and you get 30/30
for part 2 (explanation), it's over 20, and you get 10/20

This is all OK too. but note the bold I've added. You're saying part 1 is 30 marks.

Originally Posted by wyndslash

since part 1 is 30% and you got perfect there, you already get 30%

This is your error. Part 1 is 30 marks, not 30%. Part one, at 30 marks would be 24%, not 30%, of the final result.

[wyndslash]

well, yes, i'm assuming it's 30 points for that part, and that part weighs 30% of the 45%. of course, in real life, there would be more than one quiz.

[Rumpelteazer]

Taking my time this morning. After yesterday's lovely weather today it's raining again. I think I'm going to the National Gallery today, but if it keeps raining I'll probably be back early.

[pdurrant]

Originally Posted by wyndslash

well, yes, i'm assuming it's 30 points for that part, and that part weighs 30% of the 45%.

45%? 40%. And you're making the same error again. 30 marks is not the same as 30% of the final result.

Part 1 is 30 marks. That's 30 marks out of 50. So it counts for 3/5ths of the final percentage that the 50 marks counts for.

You said at the start that the 50 marks for this quiz count for 40% of the final result.

So 30 marks only counts for 3/5 of 40% = 24% of the final result.

[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

[pdurrant]

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)

[wyndslash]

i think we've reached an agreement now. and as for the marks, i only added that to indicate the total number of points for each part of the test. and yes, the weight of each component is not equal.

i ask this because i'm going to be teaching part-time next term, and the part of the grading system that was given to me resembles my question. i wanted to get it right.

the method that you showed me seems similar to the one my prof also told me i could do if the denominator of all parts 1 and parts 2 are equal (like, 30 for part 1 and 20 for part 2).

[Rumpelteazer]

I've just uploaded the pictures I took on Saturday and yesterday. Today I didn't do much. I went to the National Gallery, which looks big from the outside but doesn't have that much inside, although I did like the Punch exhibition. After that I bought some food for tonight and since it was raining hard I went back to campus and had a lazy afternoon of reading and napping. Tomorrow I'm going home but I will come back to Dublin.

[orlok]

Originally Posted by Rumpelteazer

I've just uploaded the pictures I took on Saturday and yesterday. Today I didn't do much. I went to the National Gallery, which looks big from the outside but doesn't have that much inside, although I did like the Punch exhibition. After that I bought some food for tonight and since it was raining hard I went back to campus and had a lazy afternoon of reading and napping. Tomorrow I'm going home but I will come back to Dublin.

Some great pictures, Bianca, but no people in any of them? I can't remember, did you go to Dublin on your own? Let's see some of you enjoying the Irish craic .

[Rumpelteazer]

Originally Posted by orlok

Some great pictures, Bianca, but no people in any of them? I can't remember, did you go to Dublin on your own? Let's see some of you enjoying the Irish craic .

I went alone, next time I'll drag my sister with me . I loved Dublin and I will be back, I've already made a list of things I want to do next time. Before I came I was afraid that the Dublin City University campus might be a bit too far from the city centre, but it's only a 20 minute bus ride away (getting a 7 day bus and Luas card was a very good idea) and if I come during summer next time I'll be back to DCU.

The city has beautiful spots and is clean, the people are nice and most attractions are either free or reasonably priced (unless you go to commercial things as the Guinness storehouse, that's expensive). Next time I might buy a hop-on-hop-off buspass, just because they go to some of the further away attractions. Also, next time I definately will go on some of the walking tours if weather permits (it didn't this trip).

My next holiday is planned for March or April when I'm going to Rome with my sister, I'm already looking forward to that trip!

[kindlekitten]

Originally Posted by bjones6416

I just made a shoofly pie, just because I had never tasted one and it seemed like the thing to do. I've been a baking fool lately, and not even because I want to eat any of it. I just want to bake. This is definitely a strange phase of my life.

that's our families traditional holiday breakfast!