Week 21: Examples With T- Statistics : Wrong degree of freedom and n

At 2:07, the T-statistic degree of freedom should be 4 instead of 5.

5 was the sample size.

Also, why the value of n was chosen differently in calculating the z statistic? Why n=10 was chosen in Z statistic when n=5 was used in t statistic?

I agree that was confusing - I believe that slide should be

t4,0.025 = 2.78

and n=5 too

I went through this earlier and was indeed as confused as you :slight_smile:

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Yes you’re right, that’s some error in the slides by our end.
Please check out the search results for Error: Week 21 or the posts tagges as errata.

I would not have thought to search the forum for those terms when reporting an error in the content.

Ideally the video should be fixed - and as both value appear statically on the screen this should hopefully just entail an edit rather than a re-recording (overlay or similar). The audio is accurate so no issues there.

Until then I’m sure you’ll get this issue raised many times especially as the number of students scales.

Just a thought…

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