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Re: st: uniform distribution


From   Nikos Kakouros <[email protected]>
To   [email protected]
Subject   Re: st: uniform distribution
Date   Sat, 9 Nov 2013 07:58:58 -0500

Fernando,

That seems to work pretty well (did a run below).
I'm not entirely sure why it should work though.

Is it because the normal distribution in this case works as an
approximation to the binomial distribution?

Nikos



set obs 50000
gen test=runiform()
sort test
histogram test
gen n_test=invnormal(test)
histogram  n_test, normal
swilk  n_test



On Fri, Nov 8, 2013 at 3:58 PM, Fernando Rios Avila <[email protected]> wrote:
> What about standardizing the variable toward an index from 0 to 1.
> say:
> sum mpg
> gen mpg_s=(mpg-r(min))/(r(max)-r(min))
> Transform it into a normal
> gen n_mpg_s=invnormal(mpg_s)
> and then make a normality test of this variable
> sktest n_mpg_s
> HTH
> Fernando
>
> On Fri, Nov 8, 2013 at 3:53 PM, Nick Cox <[email protected]> wrote:
>> -egen, count()- on a variable just puts a constant in a variable,
>> namely the sum of non-missing values, which is useless for your
>> purpose.
>>
>> The best test of uniformity is graphical: -quantile- by accident if
>> not design yields the appropriate graph. Otherwise think of
>> chi-square, Kolmogorov-Smirnov, etc.
>>
>> For "STATA" read "Stata".
>>
>> Nick
>> [email protected]
>>
>>
>> On 8 November 2013 18:09, PAPANIKOLAOU P. <[email protected]> wrote:
>>
>>> I am a fairly new user to STATA. I have got to check whether each of
>>> these two variables (column  2: MS_COHO; column 3: UK_MS) follow the
>>> uniform distribution.
>>> For each for them, I used the following code, properly adjusted:
>>>
>>> egen n = count (mpg)  // use MS_COHO and UK_MS each time ... drop n i
>>> surprisingly, the results were identical in both attempts, though the
>>> script was applied to two different variables.
>>> MONTH  MS_COHO     UK_MS
>>> Apri        396      62986 |
>>> Aug        330      67503 |
>>> Dec        342      65218 |
>>> Feb        348   59491.83 |
>>> Jan        379   65502.33 |
>>> Jul        377    68214.5 |
>>> Jun        368   65511.33 |
>>> Mar        419   65112.17 |
>>> May        423   66152.34 |
>>> Nov        328   65107.67 |
>>> Oct        347   68344.16 |
>>> Sep        356   67597.34
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