Excluding outliers

Some statistics can be badly affected by outliers in the data, while others are robust. It is often worth considering how the results are affected by such observations.

  1. On the Analyse-it ribbon tab, in the Report group, click Goto Dataset.

    The dataset worksheet is displayed.

  2. Click in cell A34 containing the value -44.
  3. On the Analyse-it ribbon tab, in the Dataset group, click Include / Exclude.

    The value is enclosed in square brackets [] indicating it will be excluded from further analysis.

  4. Repeat steps 2 and 3 to exclude the value -2 (cell A58).
  5. Click on the Speed worksheet tab.
  6. On the Analyse-it ribbon tab, in the Report group, click Recalculate.

    The results are recalculated without the outliers and the analysis report updated.

After excluding the outliers the mean estimate has changed from 26.2 to 27.8 and the confidence interval is narrower.