[R] Inverse Student t-value

[Andre]

Hi Duncan,

No, that's correct. Actually, I have data set below;
N= 1223
alpha= 0.05

Then
probability= 0.05/1223=0.0000408831
degree of freedom= 1223-2= 1221

So, TINV(0.0000408831,1221)  returns 4.0891672


Could you show me more detail a manual equation. I really appreciate it if
you may give more detail.

Cheers!


On Wed, Oct 1, 2014 at 1:01 AM, Duncan Murdoch <murdoch.duncan at gmail.com>
wrote:

> On 30/09/2014 1:31 PM, Andre wrote:
>
>> Dear Sir/Madam,
>>
>> I am trying to use calculation for two-tailed inverse of the student`s
>> t-distribution function presented by Excel functions like
>> =TINV(probability, deg_freedom).
>>
>> For instance: The Excel function =TINV(0.0000408831,1221) =  returns
>>   4.0891672.
>>
>> Would you like to show me a manual calculation for this?
>>
>> Appreciate your helps in advance.
>>
>
> That number looks pretty far off the true value.  Have you got a typo in
> your example?
>
> You can compute the answer to your question as abs(qt(0.0000408831/2,
> df=1221)), but you'll get 4.117.
>
> Duncan Murdoch
>
>
>

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