StatCrunch: Computing Confidence Intervals for the Difference between Two Means with Raw Data Video Lecture | Statcrunch Tutorials for Beginners - Data & Analytics

In this video you will learn to compute
confidence intervals for the difference
between two means
with raw data using StatCrunch. The
dataset I'll be using is called
"Asking prices for four-bedroom homes in
Bryan/College Station, Texas".
This dataset compares four-bedroom homes
listed for sale
into adjoining cities Bryan, Texas
and College Station, Texas. It consists of
a random sample a fifteen homes listed
for sale in Bryan,
and fifteen homes listed for sale in
College Station.
The square footage column contains the
square footage or each home,
and the location column lists the city where
the home is located.
So for this video the statistical
question going to investigate
is: "Is there a significant difference in
average size of four-bedroom homes
listed for sale in the two cities? To do
so
under the "Stat" menu I choose "T Stats",
"Two Sample", "with data"
For both sample 1 and sample 2
and the "values in" box I'll choose the
"square footage" column.
Now for sample 1 I want to limit it
only homes in Bryan, Texas, so in the
where box
I'm going to type "Location="Bryan, TX"".
Note StatCrunch is case sensitive so
this needs to appear the exact same way as
it does in the data table.
You also note that I put quotations around
because it contains a space.
Now in sample 2 I want to limit it to only
homes in College Station, Texas,
so in the where box I'll type "Location="College Station, TX"".
Under "Perform" I'm going to choose "Confidence Interval. By default StatCrunch has a value of
0.95 for the level,
which will produce a 95 percent
confidence interval for the difference
between the two means.
For this example I'll enter 0.99,
which will produce a 99 percent
confidence interval.
I'll click compute. The results show a 99
percent confidence interval for the
difference in the mean square footage
for four-bedroom homes where "L. Limit" is the lower
limit
and 'U. Limit" is the upper limit of
the confidence interval.
Lastly StatCrunch can also add our results
the data table for future
calculation. To do so under "Options",
choose "Edit". This will take us back to the
original window where we set up our
confidence interval.
Under output choose
store in data table. I'll click compute,
and now the results are stored
in new data columns for future
calculation.