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The PRC has developed an improved variant of the DF-31 called the DF-31A. This upgraded missile has a reported range of 13,200 km, [ 3 ] will allow targeting of most of the continental United States [ 7 ] and was designed with MIRV capability to hold 3 to 5 warheads, each capable of a 90 kt yield, but is thought to be armed with only one ...
The following table lists values for t distributions with ν degrees of freedom for a range of one-sided or two-sided critical regions. The first column is ν , the percentages along the top are confidence levels α , {\displaystyle \ \alpha \ ,} and the numbers in the body of the table are the t α , n − 1 {\displaystyle t_{\alpha ,n-1 ...
The DF-31 (CSS-10) is China's newest road-mobile, solid-fuel ICBM developed by the 4th Aerospace Academy (now ARMT). The DF-31 has range of 8,000+ km, and can carry a single 1,000 kt warhead, or up to three 20-150 kt MIRV warheads.
Once the t value and degrees of freedom are determined, a p-value can be found using a table of values from Student's t-distribution. If the calculated p-value is below the threshold chosen for statistical significance (usually the 0.10, the 0.05, or 0.01 level), then the null hypothesis is rejected in favor of the alternative hypothesis.
In text and tables, the abbreviation "d.f." is commonly used. R. A. Fisher used n to symbolize degrees of freedom but modern usage typically reserves n for sample size. When reporting the results of statistical tests, the degrees of freedom are typically noted beside the test statistic as either subscript or in parentheses. [6]
Most frequently, t statistics are used in Student's t-tests, a form of statistical hypothesis testing, and in the computation of certain confidence intervals. The key property of the t statistic is that it is a pivotal quantity – while defined in terms of the sample mean, its sampling distribution does not depend on the population parameters, and thus it can be used regardless of what these ...
The value of the studentized range, most often represented by the variable q, can be defined based on a random sample x 1, ..., x n from the N(0, 1) distribution of numbers, and another random variable s that is independent of all the x i, and νs 2 has a χ 2 distribution with ν degrees of freedom.
When only the equality of the two groups means is in question (i.e. whether μ 1 = μ 2), the studentized range distribution is similar to the Student's t distribution, differing only in that the first takes into account the number of means under consideration, and the critical value is adjusted accordingly. The more means under consideration ...