Math Challenge

[dubjay]

Ok - it's been a few years for me since I took a math class...so maybe you guys can help me figure this out

In our metrics system, we log video plays, along with associated success events (25% played, 50% played, etc).

So let's say we have one video that got:

25% played - 940 times
50% played - 698 times
75% played - 557 times
100% played - 398 times

What would the average % played be? And how did you go about doing that calculation?

[Abui]

940 * 25% = 235
698 * 50% = 349
557 * 75% = 418
398 * 100% = 398
_____________
2593 _____ 1400

Multiply Times by Percent and add the columns.
Then take 1400/2593 = 54%

[sladnas]

So when you say:

25% played - 940 times

There was some video that was viewed 940 times but that only represented 25% of the possible views?

Abui answered it the way I was going to...seriously

[dubjay]

Originally Posted by Abui

940 * 25% = 235
698 * 50% = 349
557 * 75% = 418
398 * 100% = 398
_____________
2593 _____ 1400

Multiply Times by Percent and add the columns.
Then take 1400/2593 = 54%

Hmm..that's what I kind of tried doing but it didn't quite work out.

Let's say I have just 1 video that played to it's completion and 1 video that played halfway (50%)

2*.25=.50
2*.50=1
1*.75=.75
1*1=1
----------------
4_____3.25

That gives 81.25% - but it really should be 75%.

Originally Posted by sladnas

So when you say:

25% played - 940 times

There was some video that was viewed 940 times but that only represented 25% of the possible views?

Abui answered it the way I was going to...seriously

The video actually started playing 1694 times, but got to the 25% mark only 940 of those times.

[sladnas]

Ok, so the video got to the 25% mark 55.5% of the time. (940/1694).

Is the data orthogonal such that things are not counted twice? For example, if a video gets to 75%, is it ONLY counted in the 75% category, or is it counted in 25%, 50% and 75%?

[dubjay]

Originally Posted by sladnas

Ok, so the video got to the 25% mark 55.5% of the time. (940/1694).

Is the data orthogonal such that things are not counted twice? For example, if a video gets to 75%, is it ONLY counted in the 75% category, or is it counted in 25%, 50% and 75%?

Yes.

If it gets to 75%, it's counted in every bucket (25%, 50%, 75%). It just adds a count to the database every time that point is reached.

[bighit8]

What is the number of people playing said video?That adds an A+B=C problem

[OffRoadie]

Originally Posted by dubjay

Hmm..that's what I kind of tried doing but it didn't quite work out.

Let's say I have just 1 video that played to it's completion and 1 video that played halfway (50%)

2*.25=.50
2*.50=1
1*.75=.75
1*1=1
----------------
4_____3.25

That gives 81.25% - but it really should be 75%.





The video actually started playing 1694 times, but got to the 25% mark only 940 of those times.

Oh, I see. So if a video plays 50%, it also gets counted in the 25% group. If that's the case, take Abui's method, but remove double counts.

Your example, 1 video, played to 50% and played to 100% would have:
2 at 25%
2 at 50%
1 at 75%
1 at 100%

The 1 at 100% is also counted in the 25%, 50% and 75% groups. Readjust counts in the those groups to remove the 100% played video:
1 at 25% (100% video removed)
1 at 50% (100% video removed)
0 at 75% (100% video removed)
1 at 100%

Next non-zero in the list is the 50% tape. It is also counted in 25% group. Readjust to remove double counts of 50% played tapes:
0 at 25% (100% and 50% video removed)
1 at 50% (100% video removed)
0 at 75% (100% video removed)
1 at 100%

Do calculation:
1*.50+1*1.00 = 1.50
1+1=2
1.5/2 = .75, or 75%

[dubjay]

Man..you guys are good. I've been thinking about it for 4 hours (on/off of course).

Thanks..beers on me next time!

[sladnas]

Cool. Yeah, I just re-factored your data and stripped the double counts so I got:

25% - 242 times
50% - 141 times
75% - 159 times
100% - 398 times

Now you should be able to use traditional methods:

.25 * 242 +
.50 * 141 +
.75 * 159 +
1.0 * 398

= 719.25

We know there were 940 total plays, so the average was 719.25/940 = 76.5%

[bighit8]

Since on subject here.I suck at math but enjoy a challenge.
3x+5>7

[sladnas]

Originally Posted by bighit8

Since on subject here.I suck at math but enjoy a challenge.
3x+5>7

3x > 2
x < 2/3

[bighit8]

Originally Posted by sladnas

3x > 2
x < 2/3

yes but x>2/3

[sladnas]

Originally Posted by bighit8

yes but x>2/3

Whoops, flew through that one too quick.

[destroyer]

⌠
⌡x3^x^2 dx

More fun!

Edit:

That's supposed to be a integration symbol.

[strobelite]

i just thought of a new extreme reality show, mtb and the geek!

[bighit8]

ok i have to go to bed but....2xSquared (not sure how to put in th other 2)+ 7x= - 6

[destroyer]

Originally Posted by bighit8

ok i have to go to bed but....2xSquared (not sure how to put in th other 2)+ 7x= - 6

You mean:

2x^2 + 7x = -6

Put into standard form:
2x^2 + 7x +6 = 0


Quadratic formula says:



x = [-7 +/- (7^2 - 4(2)(6))^(1/2)] / 2(2)

x = [-7 +/- (49 - 48)^(1/2)] / 4

x = (-7 +/- 1) / 4

x = -6/4 and -8


:drunk:

[emfc]

This thread makes my brain hurt.

[Abui]

Originally Posted by Abui

940 * 25% = 235
698 * 50% = 349
557 * 75% = 418
398 * 100% = 398
_____________
2593 _____ 1400

Multiply Times by Percent and add the columns.
Then take 1400/2593 = 54%

Double Counting! Why didn't you say so.

That makes it easier.

Add all plays--

940
698
557
398
____
2593

Take 25% of total = 648.25

Compute % 648.25 / 2593 = .6896
or 69% in round numbers


note: dubjay's simple example
add the categories:
2
2
1
1
__
6 * 25% = 1.5
1.5/2 = 75% walla!

(sladnas had a good method but a calculator error)