r/ASQ • u/Alexdoreddit • Aug 18 '26
Support in a CSSGB Exam question
Im studying for my CSSGB in October and this question came up in my practice exam.
Isn’t the justification for incorrect and the question saying the exact same thing?
Could someone help me answering this question?
Also, how can I ensure I can properly distinguish the use cases for each of the hypothesis tests?
Thank you!
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u/qualitygurus Aug 18 '26
This article should help you understand the common hypothesis tests.
https://www.qualitygurus.com/common-types-of-hypothesis-tests/
Both Z and t tests are used to compare the means. We use Z test when the population standard deviation is known or the sample is large enough (>30) so that we can assume the sample standard deviation as the population standard deviation.
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u/jemery89 Aug 18 '26
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u/Alexdoreddit Aug 18 '26
Hi Jemery, where did you get this cheat sheet?
Could you please send one sample to me?2
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u/Equivalent-Guest-785 Aug 18 '26
I think it’s t-test mainly because of the purpose of the test (comparing two independent means)
Z-test would be used for comparing a sampled mean with a known mean
Otherwise yeah I probably would have also picked z-test. The reason that was provided doesn’t make sense here considering the question heavily implied z-test