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Looks Can Be Deceiving





Acceptance Percentage Totals for the University Chart 2 Accepted Rejected Total Percent Accepted Women 450 550 1000 45% Men 175 325 500 35% Total 625 875 1500 This table shows women actually having a higher overall acceptance rate than men. This is an example of Simpson’s Paradox because it involves misleading data. Obviously, the presentation of the data is very important, and can lead to incorrect assumptions if the data are not used properly (Internet 2). Paradox 2: An Arrow in Flight One can imagine an arrow in flight, toward a target. For the arrow to reach the target, the arrow must first travel half of the overall distance from the starting point to the target. Next, the arrow must travel half of the remaining distance. For example, if the starting distance was 10m, the arrow first travels 5m, then 2.5m. If one extends this concept further, one can imagine the resulting distances getting smaller and smaller. Will the arrow ever reach the target? (Internet 3) The answer is, of course, yes the arrow will reach the target. Our common sense tells us so. But, mathematically, this fact can be proven because the sum of an infinite series can be a finite number. The question contains a premise, which implies that the infinite series will result in an infinite number. Thus, 1/2 + 1/4 + 1/8 + ... = 1 and the arrow hits the target (Internet 3). Paradox 3: Two Equals One? Assume that a = b. (1) Multiplying both sides by a, a² = ab. (2) Subtracting b² from both sides, a² - b² = ab - b² . (3) Factoring both sides, (a + b)(a - b) = b(a - b). (4) Dividing both sides by (a - b), a + b = b. (5) If now we let a = 1 = b, we conclude, from step (5), that 2 = 1.

 

Or we can subtract b from both sides and conclude that a, which can be taken as any number, must be equal to zero. Or we can substitute b for a and conclude that any number is double itself. Our result can thus be interpreted in a number of ways, all equally ridiculous. The paradox arises from a disguised breach of the arithmetical prohibition on division by zero, occurring at Step (5). Namely, since a = b, dividing both sides by (a - b) is dividing by zero, which renders the equation meaningless. As Northrop goes on to show, the same trick can be used to prove, for example, that any two unequal numbers are equal, or that all positive whole numbers are equal (Internet 4). Paradox 4: Squares and Rectangles The area of the square, shown above, is 8 x 8 = 64 units². The square is cut in the four parts A, B, C, and D, which are rearranged into the rectangle shown below. This rectangle, however, has an area of 13 x 5 = 65 units². This can lead to the potential of making 65 units² of gold out of only 64 units². How can you justify this transformation in area and the creation of matter? The picture of the rectangle is deceptive! The line XY shown in the picture of the rectangle (see above) is not a line at all. The parts XU and VY have a gradient of 2 / 5 = 0.4, and the parts XV and UY have a gradient of 3 / 8 = 0.375. So, in fact, XUYV is a parallelogram with an area of 1, not a line! Paradox 5: Where Is The Missing Dollar? Three people check into a hotel. They pay $30 to the manager and go to their room. The manager remembers that the room rate is $25 and gives $5 to the bellboy to return. On the way to the room, the bellboy reasons that $5 would be difficult to share among three people so he pockets $2 and gives $1 to each person. Now each person paid $10 and got back $1. So they each paid $9, totaling $27.

 



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