Statistical Procedure

This procedure can be used when the:

Outcome (Dependent) variable is a Continuous and Normally distributed measure
Exposure (Independent) variable is 2 independent groups

Present this graphically using a Scatter/Dot Plot

In SPSS select: Graphs > Chart Builder - Gallery – Scatter | Simple Scatter

To create the dot plot like this, the x axis variable must be numeric Nominal. Click the Element properties button and select Stack identical values. A reference line for the mean can be added by editing the exported graphic file.

Analyse this in SPSS using:

Analyze >Regression > Linear Regression
Use the Statistics button and select Confidence Intervals

Report this quoting the:

Regression Coefficients, 95% Confidence Intervals and p-value
Use the confidence intervals output by SPSS

Comments

The t-test is usually preferable.

Edit the chart to add the regression line. Select Elements > Fit Line at Total.

References

Chapter 7, p197 in Discovering Statistics using SPSS 3rd Edition, A. Field, Sage Publications (2009) (ISBN: 9781847879073)
Fitting lines to data in the Statistics for the Terrified package

Please Report any issues to Brian Yuen