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Pete A 01-21-2012 08:37 PM

Re: OT: London Cops seem to have a $54K time problem
 
On 2012-01-21 19:59:10 +0000, Richard said:

> Chris Malcolm wrote:
>> In rec.photo.digital Pete A wrote:
>>
>>> President Eisenhower expressed shock when he heard that half of all
>>> Americans are of below-average intelligence.

>>
>> I forget which newly appointed British Minister for Education reported
>> the distressing fact that half of Britain's schoolchildren were below
>> average in reading and arithmetic and promised to do something about
>> it.

>
> You made that up, didn't you?



How about these quotes:

"Schools with below average test results will be either be [sic] placed
in the special measures category or given notice to improve."

"And 1,486 state secondaries – 48.6 per cent – were below average on
the main five A* to C GCSE measure, including English and maths."

source:
<http://www.dailymail.co.uk/news/article-2002395/More-5-000-schools-face-special-measures-Ofsted-crackdown.html>



tony cooper 01-22-2012 04:26 PM

Re: OT: London Cops seem to have a $54K time problem
 
On Sun, 22 Jan 2012 09:39:38 -0500, Alan Browne
<alan.browne@FreelunchVideotron.ca> wrote:

>On 2012-01-21 19:34 , Pete A wrote:
>> On 2012-01-21 21:30:50 +0000, Alan Browne said:
>>
>>> On 2012-01-21 15:37 , Pete A wrote:
>>>> [...]
>>>> How about these quotes:
>>>>
>>>> "Schools with below average test results will be either be [sic] placed
>>>> in the special measures category or given notice to improve."
>>>
>>> Nothing wrong with that. A given school, with say 500 students, is a
>>> statistically relevant sample. It's average should be close to the
>>> national average for the same curriculum.

>>
>> Yes, one would hope so.
>>
>>>> "And 1,486 state secondaries - 48.6 per cent - were below average on the
>>>> main five A* to C GCSE measure, including English and maths."
>>>
>>> As above.

>>
>> Both quotes show total failure to understand basic statistics: if half
>> of the schools are average or above then the other half, by definition,
>> must be below average. The figure of 48.6% being below average is so
>> close to 50% that this simple logic should've been obvious to the writer.
>>
>> It's impossible to have all schools performing average or above although
>> this is what parents expect. Nobody wants their children to attend a
>> below average school.

>
>This is where you're wrong. It's impossible for all students to be
>above average.


"Impossible" was not a word chosen wisely. In this area, there are
magnet schools for the gifted. I would imagine that all of the
students in a school such as this would be above-average in
intelligence for their age group.

However, you may be thinking of a ranking of the students that attend
a specific school. Even in a school for the gifted, an average level
of intelligence can be determined and half will be above and half
below that level. The ones below might still be above-above average
compared to the general population of students in their age group.

There are also, by the way, schools in this area for students who do
not do well in the regular system. The students at these schools are
not necessarily less intelligent on average than the students in the
general population in their age group. Their inability to perform in
the regular system may be because of social and behavior issues and
not native intelligence.

I understand that intelligence does not progress as knowledge is
acquired as "age group" might indicate. It's just that comparisons of
intelligence among students is generally by age group.
--
Tony Cooper - Orlando, Florida

PeterN 01-22-2012 05:28 PM

Re: OT: London Cops seem to have a $54K time problem
 
On 1/22/2012 12:03 PM, Alan Browne wrote:
> On 2012-01-22 11:26 , tony cooper wrote:
>> "Impossible" was not a word chosen wisely. In this area, there are
>> magnet schools for the gifted. I would imagine that all of the
>> students in a school such as this would be above-average in
>> intelligence for their age group.

>
> Correct. However the context of the statement (that Pete supplied) is in
> the general school system.
>
> Quibble: it's not about 'intelligence' but performance and test results.
>


My quibble:

Assume a student population of 100.
The grade points are;
75 A
25 c

Obviously more than half the students will be above average.

--
Peter

tony cooper 01-22-2012 05:46 PM

Re: OT: London Cops seem to have a $54K time problem
 
On Sun, 22 Jan 2012 12:03:38 -0500, Alan Browne
<alan.browne@FreelunchVideotron.ca> wrote:

>On 2012-01-22 11:26 , tony cooper wrote:
>> "Impossible" was not a word chosen wisely. In this area, there are
>> magnet schools for the gifted. I would imagine that all of the
>> students in a school such as this would be above-average in
>> intelligence for their age group.

>
>Correct. However the context of the statement (that Pete supplied) is
>in the general school system.
>
>Quibble: it's not about 'intelligence' but performance and test results.


I wouldn't say that the more intelligent necessarily always perform or
test better, but I think there's enough correlation there for a
generalization. I think we've all known people who are very
intelligent who don't perform or test well, and people who are not
that bright who do very well by perseverance.

In a school for the gifted, though, there's a much stronger
correlation because they are in this school based on past performance
or testing.

Still, there's a bottom to every class.
--
Tony Cooper - Orlando, Florida

tony cooper 01-22-2012 06:00 PM

Re: OT: London Cops seem to have a $54K time problem
 
On Sun, 22 Jan 2012 12:28:35 -0500, PeterN
<peter.new@nospam.verizon.net> wrote:

>On 1/22/2012 12:03 PM, Alan Browne wrote:
>> On 2012-01-22 11:26 , tony cooper wrote:
>>> "Impossible" was not a word chosen wisely. In this area, there are
>>> magnet schools for the gifted. I would imagine that all of the
>>> students in a school such as this would be above-average in
>>> intelligence for their age group.

>>
>> Correct. However the context of the statement (that Pete supplied) is in
>> the general school system.
>>
>> Quibble: it's not about 'intelligence' but performance and test results.
>>

>
>My quibble:
>
>Assume a student population of 100.
>The grade points are;
>75 A
>25 c
>
>Obviously more than half the students will be above average.


With a skew like that, I'd challenge the validity of the testing
format.

For the past several years I've worked (very) part-time grading
standard achievement school tests. The company grades tests for
several states and for all grades from third to twelfth.

When a particular question turns up a skew like that - or the reverse
of that - the question is removed from the results. The school
systems want questions that return more right answers than wrong, but
not really a bell curve. A lop-sided bell, perhaps, that shows the
schools are doing well in teaching, but not a curve that says the
questions are too easy.

The questions, by the way, that result with a preponderance of
incorrect answers are usually badly or ambiguously phrased. It's not
that the students don't understand the problem; they don't understand
the question as written.


--
Tony Cooper - Orlando, Florida

PeterN 01-22-2012 08:34 PM

Re: OT: London Cops seem to have a $54K time problem
 
On 1/22/2012 1:41 PM, Savageduck wrote:
> On 2012-01-22 09:28:35 -0800, PeterN <peter.new@nospam.verizon.net> said:
>
>> On 1/22/2012 12:03 PM, Alan Browne wrote:
>>> On 2012-01-22 11:26 , tony cooper wrote:
>>>> "Impossible" was not a word chosen wisely. In this area, there are
>>>> magnet schools for the gifted. I would imagine that all of the
>>>> students in a school such as this would be above-average in
>>>> intelligence for their age group.
>>>
>>> Correct. However the context of the statement (that Pete supplied) is in
>>> the general school system.
>>>
>>> Quibble: it's not about 'intelligence' but performance and test results.
>>>

>>
>> My quibble:
>>
>> Assume a student population of 100.
>> The grade points are;
>> 75 A
>> 25 c
>>
>> Obviously more than half the students will be above average.

>
> ....er, not quite.
> What is above average at THAT SCHOOL?
> In your example using Grades of A & C, you have omitted an intermediary
> grade point of "B", even if no students scored "B's". In calculating a
> skewed mean for that particular test for that particular population you
> will have mean test/exam scores which fall 2/3 of the way into the "B"
> criteria. Therefore exactly the same number of students at that school
> will be above average and below average. However the skewed mean scores
> will be skewed 33.3% towards the high score.


Which of the students who scored an "A" will be below the average?


>
> Average in any given group is still average, but once you get into
> statistics things might not be what you believe they should be.
> < http://en.wikipedia.org/wiki/Skewness >
> <
> http://www.ma.utexas.edu/users/mks/s...ributions.html >
> < http://en.wikipedia.org/wiki/Mean >
>
> Now if you compare that school's scores with other schools being tested
> with the same standardized test/exam, then calculated the average for
> all of those schools, you might come to a different conclusion.
>

Proving my point that using "average" as a criteria is not always
logical. In the skew example I gave the problem is how to help those at
the bottom so that the skew will be eliminated, without moving the top
to the left.

--
Peter

Ray Fischer 01-22-2012 09:06 PM

Re: OT: London Cops seem to have a $54K time problem
 
PeterN <peter.new@nospam.verizon.net> wrote:
>On 1/22/2012 12:03 PM, Alan Browne wrote:
>> On 2012-01-22 11:26 , tony cooper wrote:
>>> "Impossible" was not a word chosen wisely. In this area, there are
>>> magnet schools for the gifted. I would imagine that all of the
>>> students in a school such as this would be above-average in
>>> intelligence for their age group.

>>
>> Correct. However the context of the statement (that Pete supplied) is in
>> the general school system.
>>
>> Quibble: it's not about 'intelligence' but performance and test results.

>
>My quibble:
>
>Assume a student population of 100.
>The grade points are;
>75 A
>25 c
>
>Obviously more than half the students will be above average.


Nope. The average is an A. No students are above average and
many are below average.

The math:
A = 4
C = 2
(75 * 4) + (25 * 2) = 350
350 / 100 = 3.5 = A (rounded to the nearest letter grade)

--
Ray Fischer | None are more hopelessly enslaved than those who falsely believe they are free.
rfischer@sonic.net | Goethe


PeterN 01-22-2012 10:07 PM

Re: OT: London Cops seem to have a $54K time problem
 
On 1/22/2012 4:06 PM, Ray Fischer wrote:
> PeterN<peter.new@nospam.verizon.net> wrote:
>> On 1/22/2012 12:03 PM, Alan Browne wrote:
>>> On 2012-01-22 11:26 , tony cooper wrote:
>>>> "Impossible" was not a word chosen wisely. In this area, there are
>>>> magnet schools for the gifted. I would imagine that all of the
>>>> students in a school such as this would be above-average in
>>>> intelligence for their age group.
>>>
>>> Correct. However the context of the statement (that Pete supplied) is in
>>> the general school system.
>>>
>>> Quibble: it's not about 'intelligence' but performance and test results.

>>
>> My quibble:
>>
>> Assume a student population of 100.
>> The grade points are;
>> 75 A
>> 25 c
>>
>> Obviously more than half the students will be above average.

>
> Nope. The average is an A. No students are above average and
> many are below average.
>
> The math:
> A = 4
> C = 2
> (75 * 4) + (25 * 2) = 350
> 350 / 100 = 3.5 = A (rounded to the nearest letter grade)
>


You didn't account for compensation for skewed curves. See the Duck's
citations.

--
Peter

Ray Fischer 01-22-2012 11:13 PM

Re: OT: London Cops seem to have a $54K time problem
 
PeterN <peter.new@nospam.verizon.net> wrote:
>On 1/22/2012 4:06 PM, Ray Fischer wrote:
>> PeterN<peter.new@nospam.verizon.net> wrote:
>>> On 1/22/2012 12:03 PM, Alan Browne wrote:
>>>> On 2012-01-22 11:26 , tony cooper wrote:
>>>>> "Impossible" was not a word chosen wisely. In this area, there are
>>>>> magnet schools for the gifted. I would imagine that all of the
>>>>> students in a school such as this would be above-average in
>>>>> intelligence for their age group.
>>>>
>>>> Correct. However the context of the statement (that Pete supplied) is in
>>>> the general school system.
>>>>
>>>> Quibble: it's not about 'intelligence' but performance and test results.
>>>
>>> My quibble:
>>>
>>> Assume a student population of 100.
>>> The grade points are;
>>> 75 A
>>> 25 c
>>>
>>> Obviously more than half the students will be above average.

>>
>> Nope. The average is an A. No students are above average and
>> many are below average.
>>
>> The math:
>> A = 4
>> C = 2
>> (75 * 4) + (25 * 2) = 350
>> 350 / 100 = 3.5 = A (rounded to the nearest letter grade)

>
>You didn't account for compensation for skewed curves.


I was pointing out the fallacy of depending on rounded values.
By definition, you cannot have more than half of the students
score above average.

--
Ray Fischer | None are more hopelessly enslaved than those who falsely believe they are free.
rfischer@sonic.net | Goethe


PeterN 01-23-2012 01:19 AM

Re: OT: London Cops seem to have a $54K time problem
 
On 1/22/2012 6:13 PM, Ray Fischer wrote:
> PeterN<peter.new@nospam.verizon.net> wrote:
>> On 1/22/2012 4:06 PM, Ray Fischer wrote:
>>> PeterN<peter.new@nospam.verizon.net> wrote:
>>>> On 1/22/2012 12:03 PM, Alan Browne wrote:
>>>>> On 2012-01-22 11:26 , tony cooper wrote:
>>>>>> "Impossible" was not a word chosen wisely. In this area, there are
>>>>>> magnet schools for the gifted. I would imagine that all of the
>>>>>> students in a school such as this would be above-average in
>>>>>> intelligence for their age group.
>>>>>
>>>>> Correct. However the context of the statement (that Pete supplied) is in
>>>>> the general school system.
>>>>>
>>>>> Quibble: it's not about 'intelligence' but performance and test results.
>>>>
>>>> My quibble:
>>>>
>>>> Assume a student population of 100.
>>>> The grade points are;
>>>> 75 A
>>>> 25 c
>>>>
>>>> Obviously more than half the students will be above average.
>>>
>>> Nope. The average is an A. No students are above average and
>>> many are below average.
>>>
>>> The math:
>>> A = 4
>>> C = 2
>>> (75 * 4) + (25 * 2) = 350
>>> 350 / 100 = 3.5 = A (rounded to the nearest letter grade)

>>
>> You didn't account for compensation for skewed curves.

>
> I was pointing out the fallacy of depending on rounded values.
> By definition, you cannot have more than half of the students
> score above average.
>


Oh! <\end sarcastic tag>

--
Peter


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