FAQ 
Calendar 


#1




Help Me Understand These Numbers
From an article in The Economist on racial distribution of students in the best New York City high schools,
...show that whites are 80% more likely than black students to take part in programmes for the gifted and Asians are three times as likely. I think this is poorly written. Maybe I am dumb. Maybe it means: 100 black students 180 white students 300 Asian students What do you think?
__________________
8002375055 Shrine Hospitals for Children (North America) Never any fee Do you know a child in need? 
#2




I'd say it's more:
Out of every 1000 students of each race.. 100 of the black students would take part 180 white students 300 asian students 
#3




The numbers simply record participation, not ability.

#4




I would take the same interpretation as Cheesesteak (with the caveat, of course, that we don't know what the common denominator is that leads to 100 black students, 180 white students, and 300 Asian students).



#5




Surely* it would mean out of every 580 students I could expect those numbers from each group. But why the heck didn't they just use a percentage?
*I mean I guess, I do not understand this.
__________________
8002375055 Shrine Hospitals for Children (North America) Never any fee Do you know a child in need? 
#6




Given the wording from the OP, "% more likely...to take part in programmes", I would parse it as:
If x% of Black students take part  the baseline likelihood  then 1.8(x)% of White students take part, and 3.0(x)% of Asian students take part. So for example 5% of Black students, 9% of White students, and 15% of Asian students. Or 2%, 3.6%, and 6%. But we aren't given what x actually is, so we can't yet say how many students out of 1000 of each race. Nor do we know what the the baseline demographics are to say what the demographics of the gifted program is. If there are 10000 Black students, 5000 White students, and 1000 Asian students in the school system, then under my interpretation the gifted program will have (for x=0.05) 500 Black, 450 White, and 150 Asian students. Last edited by brossa; 01102020 at 11:03 AM. 
#7




I, also, agree with Cheesesteak's interpretation. Assuming it's correct, the OP is guilty of the Base Rate Fallacy.
The percentage of black students who take part in programs for the gifted is not the same thing as the percentage of students in programs for the gifted who are black. 
#8




I do not like how this was written.
__________________
8002375055 Shrine Hospitals for Children (North America) Never any fee Do you know a child in need? 
#9




Neither do I, and I am surprised it came from The Economist.



#10




I think it's fairly straightforward, much along with Cheesesteak: for every black student in the programmes there are on an average 1.8 white and 3 Asian.
The stupid part is, of course, the underlying assumption that students/people can be divided into the nonoverlapping categories "Black", "White" and "Asian"..! 
#11




Quote:
Let's say the school's students are 50% white, 30% black, 10% Asian. (10% other) If each race participated in the special program at the same rate, the program participants will also be 50% white, 30% black, 10% Asian, 10% other. But instead, Asians are 3x more likely than black to participate, and whites 80% more. Which means the program participants is something like 54% white, 18% black, 18% Asian, 10% other. In other words, the white:black ratio in the special program is 3:1 instead of 1.66:1 (i.e. 80% higher than in the whole school), and asian:black ratio is 1:1 instead of 1:3 (i.e. 3 times higher). Last edited by scr4; 01102020 at 04:42 PM. 
#12




I am not certain any of us can figure this out.
__________________
8002375055 Shrine Hospitals for Children (North America) Never any fee Do you know a child in need? 
#13




I reckon scr4 has nailed it.

#14




scr4 has the meaning of what the article is actually saying. It may be that the writer of the article didn't understand what he was saying and phrased it wrong, but we have no evidence of that. This is a much more useful piece of information than simply telling the composition of the gifted program, since the composition of the gifted program would be meaningless without knowing the composition of the school as a whole.
Though, of course, the best reporting would have been to give the raw numbers. 


#15




Here is a link to the article in question: A battle over gifted education is brewing in America. It's probably behind a paywall, sadly (I subscribe, so I can't tell). The quote is from the introductory portion of the article, a relevant portion of which I will quote here:
Quote:
Unfortunately, the way in which this is referenced leaves ambiguity as to the author's intention (there is no ambiguity as to meaning). 
#16




Quote:
I think it's a relative percentage. If black students participate at a rate of 10%, and you have 1000 black students, that's 100 black students in the program. If you have 10000 black students, then 1000 are in the program. Then you'd expect 18% of white students to participate, and 30% of asian students. If black students participate at a rate off 1%, then 1.8% of white students and 3%of asian students participate. Multiply each of those percentages by the number of students in that category. So if you have a district that is largely black, then the vast majority of students in the programs will be black. They're just a smaller subset of their originating category than the other categories. I agree though, it's poorly phrased. So: black students 100,000, white students 1000, asian students 100. In the program, you have 1000 black students, 18 white, and 3 asian. Black students 1000, white 10000, asian 5000, you'll have 10 black, 180 white, and 150 asian. All with those same ratios relating to their originating groups. 
Reply 
Thread Tools  
Display Modes  

