Re: Statistical illiteracy
In [EMAIL PROTECTED] Donald Burrill wrote: On Wed, 26 Dec 2001 [EMAIL PROTECTED] wrote (edited): I came across a table of costume jewelry at a department store with a sign that said 150% off. I asked them how much they would pay me to take it all off of their hands. I had to explain to them what 150% meant, and they then explained to me how percentages are computed in the retail trade: first we cut the price in half (50%). Then we cut it in half again. Now we have cut it in half a third time. 50% + 50% + 50% = 150% off. ... ... if they advertise a 150% discount directly, without referring to the sequence of three 50% discounts, might they not be liable to legal action for misrepresentation? I would tell the clerk in the store, Ah, you get 150% off by taking 75%-off of 75%-off. I'll take it. (1/16 price vs. 50%-off 50%-off 50%-off =1/8 price). Why settle for 1/16? Take 60% off after 90% off. Or 55% after 95%. Or 50% after 100%, which ought to underline the illogic even for arithmetically illiterate retailers. -- DFB. Donald F. Burrill [EMAIL PROTECTED] 184 Nashua Road, Bedford, NH 03110 603-471-7128 This leads to a nice quiz question: what way of taking 150% off is most advantageous to the seller, and what is the most advantageous way for the buyer? Are there single optima or multiple or continuous optima, or none? (The answer will appear upside down at the bottom of the page ;-) -- == Lee Altenberg, Ph.D. E-mail: [EMAIL PROTECTED] == = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Re: Statistical illiteracy
In [EMAIL PROTECTED] Donald Burrill wrote: On Fri, 14 Dec 2001, Wuensch, Karl L wrote: I came across a table of costume jewelry at a department store with a sign that said 150% off. I asked them how much they would pay me to take it all off of their hands. I had to explain to them what 150% meant, and they then explained to me how percentages are computed in the retail trade: first we cut the price in half (50%). Then we cut it in half again. Now we have cut it in half a third time. 50% + 50% + 50% = 150% off. ... But back to your retail trade: if they advertise a 150% discount directly, without referring to the sequence of three 50% discounts, might they not be liable to legal action for misrepresentation? -- DFB. Donald F. Burrill [EMAIL PROTECTED] 184 Nashua Road, Bedford, NH 03110 603-471-7128 I would tell the clerk in the store, Ah, you get 150% off by taking 75%-off of 75%-off. I'll take it. (1/16 price vs. 50%-off 50%-off 50%-off =1/8 price). -- == Lee Altenberg, Ph.D. E-mail: [EMAIL PROTECTED] == = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
Statistical illiteracy in Assoc. Press
Today's story from the Associated Press, Study: American kids getting fatter at disturbing rate. By 1998, nearly 22 percent of black children ages 4 to 12 were overweight, as were 22 percent of Hispanic youngsters and 12 percent of whites. ...In 1986, the same survey showed that about 8 percent of black children, 10 percent of Hispanic youngsters and 8 percent of whites were significantly overweight. ...Overweight was defined as having a body-mass index higher than 95 percent of youngsters of the same age and sex, based on growth charts from the 1960s to 1980s. ... Disturbing trends also were seen in the number of children who had a body-mass index higher than 85 percent of their peers. In 1986, about 20 percent of blacks, Hipanics and whites alike were in that category. By 1998, those figures had risen to about 38 percent of blacks and Hispanics alike and nearly 29 percent of whites. I guess that means that today's children have gotten so fat, that 100% is not enough to account for them---in1986 children required105%, and by1998 a full 114% to123% was required to account for them ;-). The only way I can make sense out of this story is if these percentages use as a baseline the 50 percentile and 85 percentile body-mass index values from the 1960s. But clearly, neither the author, or the editors, either understood or cared that what they were writing was self-contradictory on its face. Can our statistical literacy have gotten that bad? It reminds me of the story that Barry Goldwater in his 1964 Presidential campaign vowed that if he were elected, no American would make less than the national average income. -- == Lee Altenberg, Ph.D. E-mail: [EMAIL PROTECTED] == = Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =
