Answer: You can conduct multiple regression analysis on NHANES using SAS Survey Procedures. However, you need to be mindful that version 9.1 of SAS Survey Procedures does not have a domain statement for subpopulation analyses. Therefore, you have to use a macro provided on the SAS website. You need to download that file, save it to your computer, and make sure to note the location, as you will use SAS code to refer to this file later. In SAS version 9.

For Jim Hall's Help program, you need to set the PAGER and HELPPATH environment variables in Autoexec.bat. Reasonable values are: Note that Joe Cosentino has written an html Help program, and we will switch to that when we have enough support for it. Unless otherwise stated, FD-DOC HOWTO documents are copyrighted by their respective authors. See similar questions...

Answer: Generally speaking, the continuous NHANES data files are organized by their collection method. For instance, if the information is collected via household interview or MEC interview, the items are mostly like stored in the Questionnaire component. If the variables of interests are lab items, they are in the Laboratory component. See similar questions...

Answer: No. Formatting and labeling variables in SAS is optional and does not need to be done for all variables in the dataset. However, it is especially useful for frequently used variables and for clarity in your output. See similar questions...

Answer: Formats and labels are user-defined tools that provide a convenient way to define variables in your SAS or SUDAAN output. Formatting is used to assign descriptive text names to numeric and character values of a variable. Labeling, on the other hand, allows you to assign descriptive titles to variable names. See similar questions...

Answer: The Continuous NHANES files are in SAS transport file format (.xpt). They can be used with any package that supports this file format. For statistical/analytical packages that do not support SAS transport file format, you need to convert the file to a different format using an appropriate software package. See similar questions...

Answer: For SUDAAN procedures it is important that you do not create a smaller subgroup based on any non weight-related groups of interest (e.g. demographic, laboratory or examination variables) in the SAS data step before executing the SUDAAN procedure. Instead, it is highly recommended that you create a subset of your sample population using the subpopn statement in the SUDAAN procedure itself and not in the SAS data step. See similar questions...

Answer: Both SAS Survey procedures (proc surveymeans) and SUDAAN version 9.1 (proc descript) produce 95% confidence intervals (CI). These 95% CIs are calculated using the Wald method, which is based on a t-statistic for the number of degrees of freedom in the entire NHANES sample. However, they do not correct for the reduction in the degrees of freedom in subdomains where not all strata and PSUs are represented. See similar questions...

Ultra320 SCSI has been released allowing for a 320MB/sec data transfer rate. The SCSI specifications allow for the future release of Ultra640 as well doubling the transfer rate again. Ultra 640 is however will not eventuate due to issues with "data skewing" and the release of Serial Attached SCSI. The release of Serial Attached SCSI (SAS) overcomes the problem of "skewing" of parallel data bits on the cable by running all communications via a Serial interface. See similar questions...

To learn about the variables in each of the RIFs, we recommend viewing the record layouts available on the ResDAC web site See similar questions...

The term ''float variable'' is actually redundant; they are simply variables whose value can ''float'' during execution. For instance: float f, g = 3; f = g; /* f ''floats'' to g */ See similar questions...

Answer: Some variables or entire data files are not publicly released due to disclosure concerns, for example, geographic identifiers. These files are only available through the Research Data Center (RDC). You may review the Data Release and Access Policy for more information. You can find more information on this topic from the link on the main section of the homepage: Access to Public and Non-Public NHANES Data Sets See similar questions...

Answer: Yes. For NHANES datasets, the use of sampling weights and sample design variables is recommended for all analyses because the sample design is a clustered design and incorporates differential probabilities of selection. Accounting for the complex sampling design of NHANES is especially critical when calculating statistical estimates and estimating standard errors of means, geometric means, percentages and other statistics. See similar questions...

Answer: If you have highly skewed variables, transformations are recommended before constructing the confidence intervals. One of the most common transformations used in the literature is the loge. We recommend that users verify that the transformed variable is normally distributed before proceeding to construct confidence intervals. Sometimes, applying the log-transformation does not necessarily yield a normally distributed random variable. See similar questions...

SAS use a variety of campaign tactics to influence decision makers in creating recreational waters free from pollution. We carry out peaceful, but hard-hitting actions to generate campaign momentum, use supportive politicians to help us in the corridors of power, and need the likes of YOU to build on that support by signing campaign postcards or writing letters. See similar questions...

SAS are a non-profit making organisation campaigning for cleaner, safer recreational water. We receive no government support and SAS funds come from individual membership subscriptions, the selling of SAS merchandise, SAS fundraising events such as the SAS Ball and sponsorship from companies looking to put back some of their profits into environmentally friendly initiatives. In addition to these, many SAS members organise their own events and donate the proceeds. See similar questions...

Firstly, become an SAS member! This provides us with much-needed funds and the more members we have, the bigger voice we have to lobby for change. Click here to JOIN Let us know of any pollution problems in your area. We rely heavily on being kept informed by our members around the country. The sooner we know about a problem, the more SAS will be able to help. Volunteer your time. Most of the help we need is based at our St Agnes office, but we also need help at some of our actions. See similar questions...

Answer: At the present time, SAS proc surveymeans does not have an option to produce geometric means and their standard errors. However, they can be obtained by running proc surveymeans on the log transformed variables to produce means and standard errors of the log transformed variable, constructing the confidence interval on the log-transformed scale, and then back transforming the endpoints. See similar questions...

Yes. You can define calculations that use any combination of variables in the data file, constants, and mathematical operators. You can simply enter the equation in the variable definition window or use Quality Analyst’s built-in, point-and-click equation builder. The calculations are dynamic--as you enter new data, calculated results appear in the target cell. Quality Analyst treats calculated variables like any other data. See similar questions...

MATLAB parses code to look for syntax errors. When the parser encounters a name with 2 or fewer arguments, it lets them pass since they might be a variable with indices. If it encounters a name with 3 or more arguments, MATLAB knows it cannot be a variable, so the error message is returned. If you don't want the parser to snag the function, specify one with 2 or fewer arguments. See similar questions...