Consider the results shown below for independent random samples taken
from two populations :
Give the point estimate of the difference, and provide a 95% confidence interval for the difference between the means.
We will start from the "TESTS" menu . Press (see screen below)
Arrow right to "TESTS" and down to choice "9 : 2 SampZInt..."
Press (you will see this screen)
Once again you must choose "Data" or "Stats". We will choose "Stats". [Recall we are entering s1, s2 for 1, 2.]
Change your settings to match the settings on these screens:
Arrow down and highlight "Calculate" ( you will see this screen)
Press (this screen will appear)
As you can see from the screen the 95% confidence interval for the difference of the means is (.83396 , 3.166 )
The point estimate can also be calculated from this screen .
It is 13.6 Ð 11.6 = 2.0 .