Two Sample Z-Interval

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 .