Create a statistical analysis and present the results.
The basic sequence of steps to create an analysis are:
An analysis report is a standard Excel worksheet containing statistics and plots calculated by a statistical analysis. You can print, send, move, copy, and save analysis reports like any other worksheet.
Along with the results of the analysis, the report includes a header that describes the analysis, the dataset and variables analyzed, who performed the analysis and when, and the version of Analyse-it used.
Analysis reports are static. If the underlying data changes, the statistics and plots do not update automatically. You must recalculate an analysis to update it. For example, if you exclude or change the value of an observation, add or remove a case, or change the active filter, you must recalculate the analysis to see the effect of the changes.
You can also edit an analysis to make changes such as adding or removing a plot, performing a statistical test, or estimating a parameter.
Change an analysis and update the report.
Recalculate an analysis when the data has changed, and you want to update the report to reflect those changes.
Exclude observations, such as outliers or influential observations, from analysis to see their effect on the results.
Before you exclude observations from the analysis, you should fully investigate them. Rather than a nuisance, outliers can sometimes be the most interesting and insightful observations in the data.
Observations to exclude from the analysis are enclosed in square brackets (for example, [65] or [Male]) in the dataset. Excluded observations are treated the same as missing values by an analysis.
We recommend you attach an Excel comment to the cell to document the reason for excluding the observation.
Change an analysis and output the results to a new report.
Print a publication-quality report of the analysis.
Set whether to print reports in color or black and white.
Print a single high-resolution chart scaled to fill a single page.
View the data analyzed and exclude observations, filter, or make other changes to it.
Set the Excel user name to show on analysis reports.
All calculations are performed using double-precision IEEE 754 standard, highly reliable numerical methods, and then tested rigorously.
To ensure that Analyse-it produces accurate results it does not use any Excel mathematical, statistical or distribution functions. Many of these functions in early versions of Microsoft Excel used poor algorithms that often produced inaccurate results. Functions like STDEV and LINEST were affected, as were add-ins that used those functions. Microsoft has now addressed most of the problems, though you may still hear warnings against using Microsoft Excel for statistical analysis.
To avoid any of these problems Analyse-it uses reliable numerical algorithms and all calculations are performed using double-precision (IEEE 754 standard, effectively 15 significant digits). We then verify the statistics are correct, and remain so, throughout the development and release process using an in-house library of thousands of validation unit-tests.
Although all results are computed to high precision, they are presented only to a practical number of decimal places based on the numerical precision of the data.
To decide how many decimal places to present the results to Analyse-it uses the Excel number format you apply to the data. From the format, the precision you are working with is inferred, and therefore the precision you likely expect in the presentation of the statistics. Statistics such as the mean, median, and standard deviation are presented to one more decimal place than the source data.
Although the statistics are presented to only a few decimal places, the Excel cell contains the full precision value. You should use the full precision value to minimize error when using it in another calculation.
If you are preparing an analysis for presentation you can set the Excel number format applied to a cell containing a statistic on the analysis report. Do not format results if you intend to edit or recalculate the analysis as your formatting changes will be lost when you update the report.
Use the full precision of a statistic when you want to use it in further calculations.