Statistics Toolkit (STATTOOLS) is a web based resource of the Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, and it provides access to statistical tests and functions that are commonly used by clinicians preparing clinical studies or analysing data. The site was first established in mid-1990s as a resource for departmental staff.

The content provided on StatTools is produced and maintained by Professors Allan Chang and Daljit Sahota. Prof Chang is Professor Emeritus of the Department of Obstetrics and Gynaecology whilst Prof Sahota is a Professor in the same Department. Whilst both Profs Chang and Sahota are experienced researchers with many peer-reviewed scientific papers in leading journals, neither is a formally trained Statistician. The material provided in STATTOOLS is therefore intended as a supplement and not a replacement for formal lectures on statistical theory and data analysis which would be provided by a formal Statistician. The content and functions provided on STATTOOLS is based on past requests received by either Profs Chang or Sahota for assistance.

Every effort has been made to compare reported results with those reported by standard statistical software such as SPSS, MEDCalc and STATA to ensure that they are accurate and reliable. However, errors and omissions may still exist, and users should assure themselves that the contents and advise provided are correct before accepting them.

Disclaimer

The Department of Obstetrics and Gynaecology of The Chinese University of Hong Kong reserves the right to amend, update and delete any information of the website without prior notice. The Department accepts no liability for any loss, change or damage howsoever arising from any use or misuse of or reliance on any information in this website.

All statistical resources are listed in each of the two index pages, which can be accessed from the menu bar on top of every page on the web site.

Index (Subjects) provides a list of pages under subject headings. As each program or explanation page often addresses more than one subject, the pages are listed repeatedly under different subject headings. This makes searching for the right information or procedures easier, but the list is very much longer to search through.

Index (Categories) provides a list of pages according to the header of the page, but clustered along statistical and research categories rather than alphabetically. This list is slightly longer, as some pages can be classified under more than one category. The list is intended for researchers who have already made decisions as to how to plan and analyse their data, and wish to look for programs that may be suitable or explanations that may help.

There are also 2 administrative links on the menu

StatTools Home Page is a link to the StatTools Home page, this page.

Contact StatTools is a link to the contact page which allows the user to contact StatTools for questions and feedback.

Clicking on the banner at the top of any page will link the user to the home page of the Department of Obstetrics and Gynaecology, and clicking on the banner at the bottom of any page will link the user to the home page of the Chinese University

Numerical precision

Non integer numerical output from StatTools are by default in 4 decimal places of precision, unless the situation warrants otherwise. Experience indicate that this is more than sufficient, and in excess of requirements in many circumstances (percent is usually presented to 1 decimal point, probability to 2 or at most 3 decimal point, t,z,F, and Chi Square have little meaning after the second decimal point, and so on). User should be aware of this redundancy, and edit numerical results before publication.

Many mathematical procedures are iterative approximations. Depending on the power of the processor, and the limits of approximation set during computation, the results may differ. In addition, as servers are continuously upgraded and becomes more powerful, results produced from the same program may change over time. Experience indicates that numerical outputs may differ as much as 0.1% to 0.3% from different sources, and similar differences may occasionally be seen between results of current computation and static tables produced previously. Users should understand the cause of these differences, and not be confused or alarmed. If in doubt, user should send questions to StatTools or consult their statistical advisor.