calculate degrees of freedom paired t test

#Calculate degrees of freedom paired t test how to#

Assumption #1: Your dependent variable should be measured on a continuous scale (i.e., it is measured at the interval or ratio level).First, let's take a look at these four assumptions: Even when your data fails certain assumptions, there is often a solution to overcome this.

#Calculate degrees of freedom paired t test how to#

This is not uncommon when working with real-world data rather than textbook examples, which often only show you how to carry out a dependent t-test when everything goes well! However, don't worry.

In practice, checking for these four assumptions just adds a little bit more time to your analysis, requiring you to click a few more buttons in SPSS Statistics when performing your analysis, as well as think a little bit more about your data, but it is not a difficult task.īefore we introduce you to these four assumptions, do not be surprised if, when analysing your own data using SPSS Statistics, one or more of these assumptions is violated (i.e., is not met). You need to do this because it is only appropriate to use a dependent t-test if your data 'passes' four assumptions that are required for a dependent t-test to give you a valid result. When you choose to analyse your data using a dependent t-test, part of the process involves checking to make sure that the data you want to analyse can actually be analysed using a dependent t-test. However, before we introduce you to this procedure, you need to understand the different assumptions that your data must meet in order for a dependent t-test to give you a valid result. This 'quick start' guide shows you how to carry out a dependent t-test using SPSS Statistics, as well as interpret and report the results from this test. If your dependent variable is dichotomous, you should instead use McNemar's test. For example, you could use a dependent t-test to understand whether there was a difference in smokers' daily cigarette consumption before and after a 6 week hypnotherapy programme (i.e., your dependent variable would be 'daily cigarette consumption', and your two related groups would be the cigarette consumption values 'before' and 'after' the hypnotherapy programme). The dependent t-test (called the paired-samples t-test in SPSS Statistics) compares the means between two related groups on the same continuous, dependent variable. Dependent T-Test using SPSS Statistics Introduction