The two spikes can be removed using the exclude 'Data Values >' option (i.e. set a maximum allowable value) or the 'Outliers' option. For this example, the 'Outliers' option was selected. 'Outliers' calculates the average and standard deviation of the remaining data points and excludes those that fall outside a range centered around the average. The range is proportional to the standard deviation and can be adjusted using the scroll bar. The final data series is shown in the lower chart. The Y-axis scale is scaled automatically to match the data range.