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Re: st: How to generate an index for the calculation of geometric mean
From
Yuval Arbel <[email protected]>
To
[email protected]
Subject
Re: st: How to generate an index for the calculation of geometric mean
Date
Tue, 11 Dec 2012 11:57:23 +0200
It's not 2.3 but rather t=1 for reduct_per==25, t=2 for
reduct_per==625, t=3 for reduct_per==15625 etc, so that when I
calculate 625^(1/2) and 15625^(1/3) I get 25
On Tue, Dec 11, 2012 at 11:46 AM, Nick Cox <[email protected]> wrote:
> I didn't understand what you want when you asked this yesterday, and
> the same applies to this repetition. Specifically, where does the 2.3
> come from? Please show the formula which produces this result.
>
> Nick
>
> On Tue, Dec 11, 2012 at 7:31 AM, Yuval Arbel <[email protected]> wrote:
>
>> I would like to generate an index variable for the calculation of the
>> geometrical mean of an unbalanced panel (namely, the exponent, which
>> makes the product a
>> geometrical mean).
>>
>> Here is an example of one panel:
>>
>> . list reduct_per y3 if appt==2862
>>
>> +---------------------+
>> | reduct~r y3 |
>> |---------------------|
>> 30. | 1 1 |
>> 31. | 1 1 |
>> 32. | 1 1 |
>> 33. | 1 1 |
>> 34. | 1 1 |
>> |---------------------|
>> 35. | 1 1 |
>> 36. | 1 1 |
>> 37. | 1 1 |
>> 38. | 1 1 |
>> 39. | 1 1 |
>> |---------------------|
>> 40. | 1 1 |
>> 41. | 1 1 |
>> 42. | 1 1 |
>> 43. | 1 1 |
>> 44. | 1 1 |
>> |---------------------|
>> 45. | 1 1 |
>> 46. | 1 1 |
>> 47. | 1 1 |
>> 48. | 1 1 |
>> 49. | 1 1 |
>> |---------------------|
>> 50. | 1 1 |
>> 51. | 1 1 |
>> 52. | 1 1 |
>> 53. | 1 1 |
>> 54. | 1 1 |
>> |---------------------|
>> 55. | 25 25 |
>> 56. | 25 625 |
>> 57. | 25 15625 |
>> 58. | 25 390625 |
>> 59. | 25 9765625 |
>> |---------------------|
>> 60. | 25 2.44e+08 |
>> 61. | 25 6.10e+09 |
>> 62. | 25 1.53e+11 |
>> 63. | 25 3.81e+12 |
>> 64. | 25 9.54e+13 |
>> |---------------------|
>> 65. | 25 2.38e+15 |
>> 66. | 25 5.96e+16 |
>> +---------------------+
>>
>>
>> The problem is that for reduct_per==1 I would like
>> the index to become a constant and remain the same until the next
>> reduct_per, which is different from zero, comes.
>>
>> Consider the example above: during the first 26 periods the index
>> should be one and and starting from the 26th period it should change
>> to 2,3 etc.
>>
>> If, on the other hand, we would have opposite descending trail (namely
>> 25 percent reduction rate from 1-25 and zero starting from the 26th
>> period), the index should be 1, 2,..,25 and then becomes a constant 25 from
>> the 26th period.
>>
>> What is the simplest way to generate such an index? Can it be done
>> without a loop?
> *
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> * http://www.ats.ucla.edu/stat/stata/
--
Dr. Yuval Arbel
School of Business
Carmel Academic Center
4 Shaar Palmer Street,
Haifa 33031, Israel
e-mail1: [email protected]
e-mail2: [email protected]
*
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