Verification of a T estimate of a mean

Enrique Comer shared this question 3 years ago
Needs Answer

Thank you in advance for your support.

There is a not expected difference in the computation of Lower and Upper Limits for the interval estimation of the Mean, using the t-distribution.

Please see the attached file. The expected limits are: [39.13, 44.81]. Could you please verify the correctness of the result in the Probability Calculator?

GeoGebra is really a great development for education and beyond. Thank you very much for your outstanding work.


E. Cómer.

Comments (3)


Are you saying that it should be

41.97 ± 2.84
instead of

41.97 ± 3.3029


It's doing this calculation under the hood

 InverseTDistribution(19, 0.988)=2.453
which seems consistent with

TDistribution(19, 2.453) = 0.988


What's your calculation that gives (39.13, 44.81)? Maybe is helpful

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