specify whether to use a linear or a logarithmic scale for the y-axis
specify a scale interval for the y-axis
show or hide major and minor gridlines
show regression lines on scatter charts 
and
bubble charts
You can change the color, style, and weight of the lines in a chart. You can apply these changes to the x-axis and y-axis lines and to the major and minor gridlines.
You can also
specify whether to use a linear or a logarithmic scale for the y-axis
specify a scale interval for the y-axis
show or hide major and minor gridlines
show regression lines on scatter charts and
bubble charts
Regression lines graphically illustrate trends in data series. Also called trend lines, they are commonly used when charting predictions. A regression line is typically a line or curve that connects two or more points in the series and then extends into the future.
You can specify the following types of regression lines to determine the position and slope of the line.
Select the y-axis or the x-axis of the chart.
In the Properties pane, under General, double-click the Axis Line, Gridlines, or Minor Gridlines property.
Choose the color, weight, and style.
To specify a linear or logarithmic scale for the y-axis, in the Properties pane, under General, set the Scale property.
To specify a scale interval for the y-axis, set the Scale Interval property.
To show minor gridlines, double-click the Minor Gridlines property, select the Show minor gridlines check box, and type a number under Number of minor gridlines.
To show regression lines, click a scatter chart or bubble chart object and, in the Properties pane, under Chart Annotations, set the Regression Line property to Show.
When you show regression lines,
you must then select their properties. Click the regression line
icon 
in the report layout and set the Line
Styles, Regression Type, and Number
of Regression Lines properties.
