I created a chart for a bivariate normal distribution. X1 follows a normal distribution with mu1 and stdev1 and likewise for X2. X1 is along the X axis. I wanted the limits to be within 4 standard deviations of the mean. mywidth and myheight were assigned beforehand. The data start on row 2 since there are titles on row 1. The data for X1 are in the 1st column. n is the number of rows of data.
mysheetname = ActiveSheet.Name
Set mychart = Sheets(mysheetname).ChartObjects.Add(Left:=mywidth, Top:=myheight + 2, Width:=400, Height:=250)
mychart.Chart.ChartType = xlXYScatter
mychart.Chart.SeriesCollection.NewSeries
mychart.Chart.SeriesCollection(1).Values = Range(Cells(outputrow + 1, outputcol + 1), Cells(outputrow + n, outputcol + 1))
mychart.Chart.SeriesCollection(1).XValues = Range(Cells(outputrow + 1, outputcol), Cells(outputrow + n, outputcol))
mychart.Chart.HasLegend = False
mychart.Chart.Axes(xlValue).MinimumScale = mu2 - 4 * sigma2
mychart.Chart.Axes(xlValue).MaximumScale = mu2 + 4 * sigma2
mychart.Chart.Axes(xlCategory).MinimumScale = mu1 - 4 * sigma1
mychart.Chart.Axes(xlCategory).MaximumScale = mu1 + 4 * sigma1