The book says, if the ‘n’ size is large enough, we can normally standardize nonnormal distribution.
I had known that the large means ‘n≥30’, but the book have not used the z-distributin.
Why I ask this question is the Kaplan 2015 lv1 note 297p’s example uses not z-distributin but t-distribution.
How much is enough?
I had known that the large means ‘n≥30’, but the book have not used the z-distributin.
Why I ask this question is the Kaplan 2015 lv1 note 297p’s example uses not z-distributin but t-distribution.
How much is enough?