U-shaped distribution

U-shaped distribution

[¦yü ‚shāpt ‚dis·trə′byü·shən]
(statistics)
A frequency distribution whose shape approximates that of the letter U.
References in periodicals archive ?
However, it is debated that the reports recommending U-shaped distribution are not representative of findings for disease outcome and are due either to statistical fluctuations associated with low numbers of cases or confounding factors not considered9.
The fracture stress curve shows an approximate U-shaped distribution with the dip angle being changed.
The laboratory results show that the fracture curve forms an approximate U-shaped distribution with the dip angle being changed, and the rockmass strength reaches its minimum value when the dip angle is 60[degrees].
The fracture stress-dip angle curve of rockmass with slow dip angle combination has a U-shaped distribution. The rockmass with a steep dip angle combination are basically controlled by the adverse structure plane.
They find a U-shaped distribution of farm yield and productivity: both large and small farms are more productive than medium-size ones.
This phenomenon does not, however, explain the second part of the U-shaped distribution: the discovery that above some threshold, large farms are more productive than even the most productive small ones.
"There is a U-shaped distribution in the relation of sleep duration and several adverse health outcomes, with seven to nine hours representing the sweet spot," says Dr.
This VA reliance measure was not only bimodal but also followed a U-shaped distribution, because most veterans tended to be either mostly or entirely reliant on VA, or hardly or not at all reliant on VA; while there was a significant proportion remaining using both VA and Medicare services.
Finally, we considered a beta-binomial model, because it is most useful in the case of extreme over-dispersion that cannot be addressed with a negative binomial model, such as U-shaped distributions with finite support bounded between 0 and 1.
For outcomes with bimodal or U-shaped distributions, the distribution is important to consider if our goals are to understand the actual distribution and to ensure that we can generate unbiased regression coefficients and mean values that generate reasonable predictions.
Acne also differs in its characteristic presentation: In women it is typically lower-face acne in a U-shaped distribution.
This U-shaped distribution of risk with respect to sleep duration has been reported previously for coronary heart disease, mortality due to any cause, and diabetes in women.