Hacker be mitigated. White hats are usually employed by the target system's owner and are typically paid (sometimes quite well) for their work. Their work is not illegal because it is done with the system owner's consent. Black hats or crackers are hackers with malicious intentions. They often steal, exploit, and sell data, and are usually motivated by personal gain. Their work is usually illegal. A cracker is like a black hat hacker, but is specifically someone who is very skilled and tries via hacking to make profits or to benefit, not just to vandalize. Crackers find exploits for system vulnerabilities
Item analysis Item analysis Within psychometrics, Item analysis refers to statistical methods used for selecting items for inclusion in a psychological test. The concept goes back at least to Guildford (1936). The process of item analysis varies depending on the psychometric model. For example classical test theory or the Rasch model call for different procedures. In all cases, however, the purpose of item analysis is to produce a relatively short list of items (that is, questions to be included in an interview or questionnaire) that constitute a pure but comprehensive test of one or a few psychological constructs. To carry out the