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I'm trying to classify images appearing in HTML into photographs / non-photographs.
Two possible indicators (among many others) I can use are whether the image tag has an alt attribute and whether the image has a title attribute set.
In my data set I've found that about 90% of photographs have an alt attribute set; and about 60% of non-photographs have an alt attribute set. Also, about 20% of photographs have a title attribute set; and about 5% of non-photographs have a title attribute set.
How can I calculate the probability of an image being either photograph or non-photograph for every possible (true/false) configuration of the two input variables?
I think that this is just Bayesian conversion of Pr(H|D) to Pr(D|H), but I've not found a simple explanation of how to do that with more than one input variable. (And yes, let's assume that the title/alt attribute presences are independent).
-- Clairvoyant walrus2 ( talk) 00:16, 13 January 2008 (UTC)
Ok, I see now. Thanks. The answer had been staring me in the face. I implemented it in my application and it works well. -- Clairvoyant walrus2 ( talk) 04:17, 14 January 2008 (UTC)
When doing questions for an exam and comparing them with a friend we realise that we had different formulas for standard deviation and thus were getting different answers.
mine was
where as his was
both of us had found different books showing each, which one is correct. The question was to find the confidence interval. —Preceding unsigned comment added by 136.206.1.17 ( talk) 11:10, 13 January 2008 (UTC)
As part of the solution of a newspaper puzzle, I have 10 sets of 5 distinct internal angles of a cyclic pentagon. In each case, the angles could be put into 12 distinguishable sequences of occurrence round the pentagon (e.g. ABCDE, BCDEA, AEDCB are non-distinguishable in the sense of giving the same figure, turning over if necessary). My question is twofold:
1) Can any sequence of 5 positive numbers summing to 540° be drawn as a cyclic pentagon with internal angles in that order, and if so, how? 2) Can it be established without drawing whether or not the centre of the circumscribing circle is inside the pentagon?
For example, one of my sets is (171°,161°,131°,44°,33°). Having to assess 120 pentagons seems wildly excessive for the purposes of the puzzle. 86.152.78.37 ( talk) 16:34, 13 January 2008 (UTC)
Imagine I evaluate following expression
and get 2 as its limit. I factored both the numerator and the denominator as much as I could and that's the result I got. What I would like to know is prove it indeed is 2. I suppose I could check with a graphic calculator, but I would like to be able to do it using Heine's method. It needn't be the above expression, that was just an example. Any limit will do it, just in case someone thinks I am here just to have my homework solved for me. That's not the case. Thank you very much in advance. -- Ishikawa Minoru ( talk) 17:46, 13 January 2008 (UTC)
Can someone at this desk take a look at the above article. It was created by a newbie and needs cleanup but I don't know enough to do it myself. Theresa Knott | The otter sank 18:03, 13 January 2008 (UTC)
Math question on special right triangles and how to calculate their area's
Now then, isn't that easier on the eyes? ;-)
Okay, for Geometry we have this problem to do and I completly forgot how to do it. It has something to do with a special right triangle and calculating it's area. I don't wanna know just the answer but how to get to it. The question is a diagram of a 45-45-90 triangle and the 'taller' side is 73. The hypotenuse and base are unlabeled. The right angle is where the 'taller' side and bottom base meet. —Preceding unsigned comment added by 80.148.25.183 ( talk) 19:34, 13 January 2008 (UTC)
Mathematics desk | ||
---|---|---|
< January 12 | << Dec | January | Feb >> | January 14 > |
Welcome to the Wikipedia Mathematics Reference Desk Archives |
---|
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
I'm trying to classify images appearing in HTML into photographs / non-photographs.
Two possible indicators (among many others) I can use are whether the image tag has an alt attribute and whether the image has a title attribute set.
In my data set I've found that about 90% of photographs have an alt attribute set; and about 60% of non-photographs have an alt attribute set. Also, about 20% of photographs have a title attribute set; and about 5% of non-photographs have a title attribute set.
How can I calculate the probability of an image being either photograph or non-photograph for every possible (true/false) configuration of the two input variables?
I think that this is just Bayesian conversion of Pr(H|D) to Pr(D|H), but I've not found a simple explanation of how to do that with more than one input variable. (And yes, let's assume that the title/alt attribute presences are independent).
-- Clairvoyant walrus2 ( talk) 00:16, 13 January 2008 (UTC)
Ok, I see now. Thanks. The answer had been staring me in the face. I implemented it in my application and it works well. -- Clairvoyant walrus2 ( talk) 04:17, 14 January 2008 (UTC)
When doing questions for an exam and comparing them with a friend we realise that we had different formulas for standard deviation and thus were getting different answers.
mine was
where as his was
both of us had found different books showing each, which one is correct. The question was to find the confidence interval. —Preceding unsigned comment added by 136.206.1.17 ( talk) 11:10, 13 January 2008 (UTC)
As part of the solution of a newspaper puzzle, I have 10 sets of 5 distinct internal angles of a cyclic pentagon. In each case, the angles could be put into 12 distinguishable sequences of occurrence round the pentagon (e.g. ABCDE, BCDEA, AEDCB are non-distinguishable in the sense of giving the same figure, turning over if necessary). My question is twofold:
1) Can any sequence of 5 positive numbers summing to 540° be drawn as a cyclic pentagon with internal angles in that order, and if so, how? 2) Can it be established without drawing whether or not the centre of the circumscribing circle is inside the pentagon?
For example, one of my sets is (171°,161°,131°,44°,33°). Having to assess 120 pentagons seems wildly excessive for the purposes of the puzzle. 86.152.78.37 ( talk) 16:34, 13 January 2008 (UTC)
Imagine I evaluate following expression
and get 2 as its limit. I factored both the numerator and the denominator as much as I could and that's the result I got. What I would like to know is prove it indeed is 2. I suppose I could check with a graphic calculator, but I would like to be able to do it using Heine's method. It needn't be the above expression, that was just an example. Any limit will do it, just in case someone thinks I am here just to have my homework solved for me. That's not the case. Thank you very much in advance. -- Ishikawa Minoru ( talk) 17:46, 13 January 2008 (UTC)
Can someone at this desk take a look at the above article. It was created by a newbie and needs cleanup but I don't know enough to do it myself. Theresa Knott | The otter sank 18:03, 13 January 2008 (UTC)
Math question on special right triangles and how to calculate their area's
Now then, isn't that easier on the eyes? ;-)
Okay, for Geometry we have this problem to do and I completly forgot how to do it. It has something to do with a special right triangle and calculating it's area. I don't wanna know just the answer but how to get to it. The question is a diagram of a 45-45-90 triangle and the 'taller' side is 73. The hypotenuse and base are unlabeled. The right angle is where the 'taller' side and bottom base meet. —Preceding unsigned comment added by 80.148.25.183 ( talk) 19:34, 13 January 2008 (UTC)