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Re: st: exponential extrapolation
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: exponential extrapolation
Date
Tue, 1 Mar 2011 09:03:43 +0000
In fact a look at the archives shows that you asked essentially the
same question on 11 February, and unsurprisingly got a very similar
answer from Maarten Buis and myself.
So, what is going on? Perhaps you need to find someone in your
institution who can talk you through these things.
Incidentally, a plot of these data suggests to me that exponential
decline is not the right model. There is curvature not taken out by
looking at the data on log scale. Extrapolating the wrong model over
more than 5 times the range of the observation strikes me as a bad
idea, unless there is a compelling biological argument to the
contrary.
Nick
On Tue, Mar 1, 2011 at 8:27 AM, Nick Cox <[email protected]> wrote:
> This looks more as if you have an exponential decline, not an
> exponential distribution.
>
> As with your previous questions, fit an appropriate model using one or
> more of -regress- after transformation, -glm- with log link, or -nl-.
> Then use -predict-.
>
> Nick
>
> On Tue, Mar 1, 2011 at 7:00 AM, ipianah nic <[email protected]> wrote:
>
>> my data set exhibits an exponential distribution.how can I
>> extrapolate my data set as in the case below where i have genomes and
>> csf..help please
>>
>> genomes csf
>> 1 2045
>> 2 1793
>> 3 1715
>> 4 1665
>> 5 1637
>> 6 1613
>> 7 1596
>> 8 1579
>> 9 1566
>> 10 1554
>> 11 1539
>> 12 1527
>> 13 1516
>> 14 1511
>> 15 1497
>> 16 1486
>> 17 1480
>> 18
>> 19
>> 20
>> 21
>> 22
>> 23
>> 24
>> 25
>> 26
>> 27
>> 28
>> 29
>> 30
>> 31
>> 32
>> 33
>> 34
>> 35
>> 36
>> 37
>> 38
>> 39
>> 40
>> 41
>> 42
>> 43
>> 44
>> 45
>> 46
>> 47
>> 48
>> 49
>> 50
>> 51
>> 52
>> 53
>> 54
>> 55
>> 56
>> 57
>> 58
>> 59
>> 60
>> 61
>> 62
>> 63
>> 64
>> 65
>> 66
>> 67
>> 68
>> 69
>> 70
>> 71
>> 72
>> 73
>> 74
>> 75
>> 76
>> 77
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>> 80
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>> 96
>
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