To produce a scatterplot of time by diam, from the menus choose:

Graphs
Scatter...

Click Define.

Select time as the y variable and diam as the x variable.

Click OK.

These selections produce the scatterplot.

To see a best-fit line overlaid on the points in the scatterplot, activate the graph by double-clicking on it.

From the Chart Editor menus choose:

Chart
Options...

Select Total in the Fit Line group.

Click OK.

The resulting scatterplot appears to be suitable for linear regression, with two possible causes for concern.

- The variability of polishing time appears to increase with increasing diameter.

- The point on the far right of the graph may exert an undue amount of influence on the lay of the regression line.

You will investigate these concerns further during diagnostic checking of the regression model.