Welcome to College Confidential!

The leading college-bound community on the web

Sign Up For Free

Join for FREE, and start talking with other members, weighing in on community discussions, and more.

Also, by registering and logging in you'll see fewer ads and pesky welcome messages (like this one!)

As a CC member, you can:

  • Reply to threads, and start your own.
  • Post reviews of your campus visits.
  • Find hundreds of pages of informative articles.
  • Search from over 3 million scholarships.
Please take a moment to read our updated TOS, Privacy Policy, and Forum Rules.

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.
This discussion has been closed.