# T-tests and z-tests

How many variables are in a Z and T test? What are they? What are their levels of measurement?

What is the underlying difference between the T-test and the Z-test?

Provide an example of nominal information and write a work related survey question that would collect nominal data:

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#### Solution Preview

A.

A z test is typically used to compare a single sample to a population on a single variable. For example, you could use a z test to test whether a group of people are overweight relative to the rest of the population. A z test can also be used to determine whether a single individual's score is typical in a population. For example, if you took an IQ test, your performance on the test may be described in terms of a z score. Again, this would be done for a single variable (IQ). Z tests can handle a variety of different variables, but they must be measured on a continuous, interval or ratio scale of measurement.

A t test can be used to compare the following: a single sample to a population, two samples, or paired scores (for example, if you wanted to compare pre- ...

#### Solution Summary

Explains z and t tests and their underlying differences. Also gives an example of a survey question that would collect nominal data.