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A scientific specification to identify the quality of an individual sample, an entire population, or an individual test instance. As a practical term, an experiment. As nouns, adjectives relating to the sample: a rigorous scientific test; a controlled experiment. Derived from the Greek term demos, which means “of a group”.

A set of t-tests used to compare two sample sets in order to identify whether one variable is significantly associated with another and whether the other variable is significantly related to the first one. There are two concepts involved in t-testing: independence of variables and sample size. An example of a set of t-statements would be: set 1 | set 2 | t-statements | probability | variable} A hypothesis test states that there is a relationship between a specific variable and its dependent variable. In a common practice, there are two types of hypothesis testing: the null hypothesis and the alternative hypothesis. For a null hypothesis, there is no reason to assume that a variable does not exist, whereas for an alternative hypothesis, there could be a valid relationship between the variable and its corresponding sample.

A chi-squared test calculates the probability density function of the data set used in a particular study. The chi-square statistic is formulated as: where N is the number of sample points, I is the intercept and chi is the distribution function for the data set. The area under the curve of I is called the chi squared value. Correlated confidence intervals are calculated by connecting the data points for each variable, and their squares with the corresponding confidence interval. The chi-squared value is a continuous function that evaluates the value of the correlated variable I against the corresponding time variable t, where I represents the time variable and t represents the independent variable.

For cases where multiple t-statements are needed to reach the expected result, the multiple t-test approach can be applied. For example, if N is the number of items to be tested and C is the number of items to be excluded in the test case, then N x C will be the number of new item values that will be generated when C is run through the t-test model. The expected results will be the expected number of new items when C is entered into the model; however, when C is run, it may generate an item value of zero, hence the use of the accept maximum expectation approach. Accept maximum expectation approaches assumes that there will be a significant number of false results, and therefore there is a need to accept at least ten characters in the input data set in order to obtain statistically significant results.

When performing t-tests, the null hypothesis should always be rejected at p>0.1 unless there is strong evidence to suggest that the null hypothesis is true. Other than this, all other variables should be analyzed in the same way as described above. There is no need to perform more than one test under the same conditions as described above for the same variable, unless there are significant differences between the null hypothesis and alternative forms of t-tests. Additional information about multiple tests and their sample sizes can be obtained from vendors. Test examples can be found on the web at the statistics reference sites.