Question

Thirty three different video games showing violence were observed. The duration times of violence ​(in seconds) were recorded. When using this sample for a t test of the claim that the population mean is greater than 72 ​sec, what does df​ denote, and what is its​ value?

Answer 1

The "df" stands for "degrees of freedom", and represents the number of independent observations in a set of data.

Its value in this case is df=32.

Explanation:

The sample is of size n=33.

As we do not know the population's standard deviation, we use as estimate the sample's standard deviation. Because of this, we use the t-statistic in place of the z-value.

The "df" stands for "degrees of freedom", and represents the number of independent observations in a set of data (the data in this case is the sample of 33 video games).

In one-sample tests, the degrees of freedom are calculated as:

`df=N-1=33-1=32`