T-tests Flashcards
Which is more variable: t or z?
t is more variable
Why is t more variable than z?
It’s more variable because xbar and s both vary in the function for t, but z only varies due to xbar.
Is t normally distributed?
No
How does a t distribution compare to a z distribution?
It has thicker tails
When s is small, t is _______ extreme.
more
How do you calculate degrees of freedom?
n-1
What does a paired t-test measure?
It compares two means instead of one
When should you use a paired t-test?
When the samples are NOT independent
Why do we use s in place of sigma for t-tests?
We do not usually know the value of sigma
Statistical significance refers to _______.
the result of the hypothesis test
What type of t-test do you use when the two variables are dependent?
Paired t-test
What type of t-test do you use when the two variables are independent?
2 sample t-test
When we have two means, we are usually interested in a hypothesis test of _______.
the difference between them
What type of t-test do you use when you have one variable?
1 sample t-test
What is the difference between a 1-sample and a paired t-test?
A paired t-test is done over the difference between two sets of dependent data and a 1 sample test is over one set of data
