Search results
Results from the WOW.Com Content Network
In full generality, the accelerated failure time model can be specified as [2] (|) = ()where denotes the joint effect of covariates, typically = ([+ +]). (Specifying the regression coefficients with a negative sign implies that high values of the covariates increase the survival time, but this is merely a sign convention; without a negative sign, they increase the hazard.)
For example, "Able Seaman Smith; lie aft!" or "What's happening aft?". Comparative is "after", e.g. "the mizzenmast is after than the mainmast". The difference between "aft" and "stern" is that aft is the inside (on board) rearmost part of the vessel, while stern refers to the outside (offboard) rearmost part of the vessel. The stern is ...
The above methods are inappropriate to use if the pretest probability differs from the prevalence in the reference group used to establish, among others, the positive predictive value of the test. Such difference can occur if another test preceded, or the person involved in the diagnostics considers that another pretest probability must be used ...
The sign test is a statistical test for consistent differences between pairs of observations, such as the weight of subjects before and after treatment. Given pairs of observations (such as weight pre- and post-treatment) for each subject, the sign test determines if one member of the pair (such as pre-treatment) tends to be greater than (or less than) the other member of the pair (such as ...
Tukey’s Test (see also: Studentized Range Distribution) However, with the exception of Scheffès Method, these tests should be specified "a priori" despite being called "post-hoc" in conventional usage. For example, a difference between means could be significant with the Holm-Bonferroni method but not with the Turkey Test and vice versa.
The simplest test to evaluate whether a coal is suitable for production of coke is the free swelling index test. This involves heating a small sample of coal in a standardised crucible to around 800 degrees Celsius (1500 °F). After heating for a specified time, or until all volatiles are driven off, a small coke button remains in the crucible.
When the fore-aft center of gravity (CG) is out of range, serious aircraft control problems can occur. The fore-aft CG affects the longitudinal stability of the aircraft, with the stability increasing as the CG moves forward and decreasing as the CG moves aft. With a forward CG position, although the stability of the aircraft increases, the ...
Calcium aluminates can form complex salts in combination with different types of anions.Two series of calcium aluminates are known in cement chemistry: AFm and AFt phases, being respectively mono- or tri-substituted with a given divalent anion X (e.g. SO 2− 4, CO 2− 3, or hosting a divalent impurity such as SeO 2− 4 [3]...), or with two units of a monovalent anion, e.g. OH −, Cl − ...