This procedure can be used when the:

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

Present this graphically using a Scatter/Dot Plot

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

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

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 Confidence Interval Analysis (CIA)Regression and Correlation | Slope of Single Line to calculate these values

References

Please Report any issues to Brian Yuen