No connecting lines in a scatter graph

We will probably need to see the file to be able to help.

My first thought is that the data in your source range is not arranged contiguously -- there are empty cells in between data points. Excel's default is probably set to "leave gaps" for empty cells. What you probably need to do is go into the select source dialog, click on the "hidden and empty cells" button, and tell Excel to connect with a line rather than leave a gap. http://office.microsoft.com/en-us/ex...555.aspx?CTT=1

See if that helps.

If I am seeing the correct points, this is an artifact of the cubic spline algorithm Excel uses to create its smoothed curves in charts. It is especially noticeable when slope changes dramatically around a point, as it does in this region. A few possible suggestions:

1) Create your own cubic spline algorithm and plot your own connecting line. These kind of algorithms are mathematically intense, so it is probably only appropriate for those with the math and programming skills to tackle it.

2) Easiest approach is probably to uncheck the "smoothed line" box in the line style section of the format data series dialog. This will leave the data series looking "choppy", but it eliminates these kind of issues with the smoothing algorithm.

3) If you must have a smoothed line and you do not want to leave it to Excel, you could create some "dummy points" around each offending data point. You can then use these "dummy points" to control how much curvature is used around each data point.
To avoid having extra data markers show up, you will probably want to have two data series. The existing data series will be formatted without lines and left as is. You will then have another range containing these data points plus your dummy data points in the spreadsheet and linked to the chart and formatted as smoothed line without markers. Then you can tinker with the dummy points until the line looks the way you want it.