Chi-square distribution | definition of chi-square distribution by Medical dictionary
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a variable is said to have a chi-square distribution with K degrees of freedom if it is distributed like the sum of the squares of K independent random variables, each of which has a normal (gaussian) distribution with mean zero and variance one. The chi-square distribution is the basis for many variations of the chi-square(d) test, perhaps the most widely used test for statistical significance in biology and medicine.
in statistical terms this is said of a variable with K degrees of freedom if it is distributed like the sum of the squares of K independent random variables each of which has a normal distribution with mean zero and variance of 1.
References in periodicals archive
which has a chi-square distribution
with degrees of freedom equal to the number of variables.
This is compared with the appropriate chi-square distribution
to yield a chance probability.
The number of deaths at many hospitals was small, as low as 0 for many common conditions, suggesting that use of the chi-square distribution
might be inappropriate.
1, which is the 95th percentile of a chi-square distribution
with five degrees of freedom, and the 50.
2] has an independent chi-square distribution
with v degrees of freedom, then
The value calculated from this formula can then be compared to a chi-square distribution
with J-1 degrees of freedom in order to test [H.
Appendix D: Percentiles of the Chi-Square Distribution