Microsoft Office Tutorials and References

In Depth Information

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ERROR BARS

With Excel, you can easily generate error bars to

provide an estimate of the potential error in

experimental or sampled data. In science, marketing,

polling, and other fields, people make conclusions

about populations by sampling the population or

devising controlled experiments. When data is

sampled or generated in laboratory conditions, the

resulting numbers approximate the larger reality

you are exploring. An error bar shows the range of

possible values for these experimentally derived

numbers. With Excel, you can show the range of

possible values in several ways: as a fixed number,

measured in the same units used to measure data,

above or below each data point in your data series;

as a percentage of the data point; or in terms of

standard deviation units.

Standard deviation units indicate whether an

experimental number is reasonably close to the

population characteristic being studied. For example,

you can have a confidence level of 95 percent that the

population mean falls within two standard deviation

units of the sampled mean, which you know.

1

Click your chart.

The Chart tools become

available.

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2

Click the Layout tab.

3

Click Error Bars in the Analysis

group.

A menu appears.

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Click More Error Bars Options.

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Alternatively, click the

appropriate menu option.

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