Determining dfs for independent & dependent t test?

W

Wood

Guest
#1
How are the dfs determined for the independent t test and dependent t test?

I looked at the question and drew a blank. I'm not that good in math. I don't even know where to begin. Thanks in advance for your help!

regards,
W.D.
 
#2
Remember that the df of a t distributed statistic T is determined by the df of the denominator W~Chisq_df,

T=Z/(W^{1/2})

While the df in denominator has many ways to interpret. For example, #of observations-#of parameters to be estimated.
For example:

are i.i.d. N(μ,σ2) random variables, then
where
.