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AP Stats Question

mikeunlachermikeunlacher Registered User Posts: 123 Junior Member
edited May 2009 in AP Tests Preparation
Could someon please give me a list of all possibile situations that I would use the 2 sample Z test or 1 Sample Z Test. It seems to always be T-Tests cuz every scenario is takes data from a Random Sampling and thus the standard deviation is of the sample and never the population. Thanks in advance.

Replies to: AP Stats Question

  • jliujliu Registered User Posts: 244 Junior Member
    T-test is used when you do not know the standard deviation of the population (which is almost always). or in other words, if you know the SD of the sample.
    z-test is mostly used when standard deviation of the pop. is given, or for proportion testing or estimating the binomial distribution. It should specifically say something like "the standard deviation for the population of students in ohio is .... sample was taken from students in 4 counties". If you're not sure I'd just go with a t-test. and between matched pairs and 2-sample t test, 2 sample requires independent samples.
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