[R] Homework help: Is this how CIs of normal distributions are computed?

Zembower, Kevin kzembowe at jhuccp.org
Wed Oct 31 22:00:51 CET 2007

Dan, I didn't realize that the t values were more accurate than the
normal approximation for n > about 30. I may have learned (incorrectly)
that the normal distribution should be used if n > 30, but now that I'm
thinking about it, this may have just been computationally economical
before computers.

Thanks for this thought.


Dan Nordlund wrote:

You could probably use the Normal distribution as an approximation under
these circumstances, but why would you when you have a more accurate CI
using t.test?


Daniel J. Nordlund
Research and Data Analysis
Washington State Department of Social and Health Services
Olympia, WA  98504-5204

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