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Re: st: calculate maximum density of normal distribuion
From
Nick Cox <[email protected]>
To
"[email protected]" <[email protected]>
Subject
Re: st: calculate maximum density of normal distribuion
Date
Fri, 22 Nov 2013 15:34:14 +0000
If you know the mean, that fixes the position of the maximum; why do
you need any other information?
Nick
[email protected]
On 22 November 2013 15:32, Nick Bornschein <[email protected]> wrote:
> Thanks, that worked!!
>
> And now is the question: can I tell the xline (which is the mean) to end at
> the maximum point somehow?
>
>
>
> Am 22.11.13 16:29, schrieb Maarten Buis:
>
>> The mean won't do anything for the maximum, but the maximum is a
>> function of the standard deviation. It has to be otherwise the it
>> would not integrate to 1. So -normalden(0,$sd2)- will give you the
>> maximum.
>>
>> -- Maarten
>>
>>
>> On Fri, Nov 22, 2013 at 4:23 PM, Nick Bornschein
>> <[email protected]> wrote:
>>>
>>> Well, no.
>>>
>>> The maximum density of a normal distribution of mean = 1 and sd = 2 is
>>> around 0.2 (looking at the graph) and with mean = 5 and sd = 3 it's
>>> around
>>> 1.125...so it's not always the same when I change the given mean and sd.
>>>
>>>
>>> Am 22.11.13 16:12, schrieb Nick Cox:
>>>>
>>>>
>>>> That density is a constant, namely
>>>>
>>>> . di normalden(0)
>>>> .39894228
>>>>
>>>> Whatever mean a normal has just shifts the distribution left or right,
>>>> so makes no difference to what the peak density is; hence without loss
>>>> of generality we can focus on mean 0.
>>>>
>>>> Whatever SD a normal has, 0/SD is still 0.
>>>>
>>>> Correct me if I'm wrong....
>>>> Nick
>>>> [email protected]
>>>>
>>>>
>>>> On 22 November 2013 15:00, Nick Bornschein <[email protected]>
>>>> wrote:
>>>>>
>>>>>
>>>>> Hello,
>>>>>
>>>>> I'm calculating a normal distribution with:
>>>>>
>>>>> set obs 10000
>>>>> set seed 2211
>>>>> gen normal2 = rnormal($mean2, $sd2)
>>>>>
>>>>> by given mean and sd which I define via global macro.
>>>>>
>>>>> Is it possible to calculate the maximum density at the mean point?
>>>>> And more interesting: is it possible to define "xline" until a given
>>>>> point
>>>>> at the y axis (the maximum density as you can imagine) because I want
>>>>> to
>>>>> add
>>>>> the mean line with going higher than the maximum density?
>>>>>
>>>>> Best
>>>>> -Nick
>>>>> *
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>>>>
>>>>
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>>
>>
>>
>>
> *
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