Question

Suppose a researcher wishes to construct a 90% ?-confidence interval for the difference of two independent means with unknown population standard deviations. His sample sizes are ?1=8 and ?2=12, and his calculated Satterthwaite approximate degrees of freedom are 15.756.

What is the positive ?‑critical value for this confidence interval, rounded to 3 decimal places?

? =

Answer 1

I would like to share with you that in the excel there is a function =t.inv from which we can find the t critical values where we have to put two things

1) Value of Alpha

2) Degrees of freedom

If you want to test for a two tail test then divide alpha by 2 . Let me show you practically we have ALPHA = 0.05

Hit enter

Hence positive value of Apha is 1.75305.

If you want to test for Apha is 0.1 or 10 % , then you can try for that also .

(Thanks - Hit like )