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100 Useful Tips and Tools to Research the Deep Web. By Alisa Miller Experts say that typical search engines like Yahoo! And Google only pick up about 1% of the information available on the Internet. The rest of that information is considered to be hidden in the deep web, also referred to as the invisible web. So how can you find all the rest of this information? This list offers 100 tips and tools to help you get the most out of your Internet searches. Meta-Search Engines Meta-search engines use the resources of many different search engines to gather the most results possible.

SurfWax. Semantic Search Tools and Databases Semantic search tools depend on replicating the way the human brain thinks and categorizes information to ensure more relevant searches. Hakia. General Search Engines and Databases These databases and search engines for databases will provide information from places on the Internet most typical search engines cannot. DeepDyve. Academic Search Engines and Databases Google Scholar. Scientific Search Engines and Databases. Welcome to the NASA Star and Exoplanet Database. Best Free Astronomy Software. Aladin Runs as a stand-alone program on a user's computer View stars and deep space objects--all of them that have been imaged. Actual images in different wavelengths. Also density maps and other databases. Excellent index of stars and deep space objects. Bookmarks. No solar system objects. 7.015b Unrestricted freeware There is no portable version of this product available.

Windows, Mac, Linux Java 1.5 and an internet connection required. Sky-Map.org Is a web service or web application Image viewer of stars and deep space objects. Web based Computer Aided Astronomy (aka C2A) Great index. No satellites, e.g. no International Space Station. Windows only Internet connection needed to access Sky Surveys Cartes du Ciel (aka Skychart) Excellent index. 32 bit but 64 bit compatible Open source freeware Stellarium Stars shown in spectral colors. Few comets and asteroids in the catalog.

A portable version of this product is available but not from the developer. Windows, Linux, Mac WorldWide Telescope No moon phases. Quadratic Equation Calculator. The T-Test. The t-test assesses whether the means of two groups are statistically different from each other. This analysis is appropriate whenever you want to compare the means of two groups, and especially appropriate as the analysis for the posttest-only two-group randomized experimental design. Figure 1 shows the distributions for the treated (blue) and control (green) groups in a study. Actually, the figure shows the idealized distribution – the actual distribution would usually be depicted with a histogram or bar graph.

The figure indicates where the control and treatment group means are located. The question the t-test addresses is whether the means are statistically different. What does it mean to say that the averages for two groups are statistically different? This leads us to a very important conclusion: when we are looking at the differences between scores for two groups, we have to judge the difference between their means relative to the spread or variability of their scores.