Equivalence practical significance

The two-sample t-test (4). Statistical significance, practical significance and equivalence... 

Explain how to test for equivalence (i.e. show that two measured outcomes do not differ to an extent that is of practical significance)... 

The first three cases are unambiguous, (a) is detrimental and definitely of practical significance. We are pretty confident that even the minimum effect (a reduction of 7.5 g/1) is large enough to cause practical harm, (b) definitely has no practical significance the whole Cl is within the equivalence zone, (c) is beneficial and definitely of practical significance. The most pessimistic view would be that there is an increase of 7 g/1, which is still enough to be useful. 

To demonstrate that a treatment produces an effect great enough to be of practical significance, we must show that the 95 per cent Cl for the size of the treatment effect lies entirely to one side of the equivalence zone. 

Since we cannot demonstrate exact equality, we turn instead to practical equivalence. We try to demonstrate that any possible difference between two outcome is too small to be of practical significance. 

However, there is still the question of where we are going to put those pesky equivalence limits. In the first case, we will adjust them nice and close to zero, then even our pathetic effort will cause a practically significant difference. For the latter two, we will invent some reason to set them generously wide and hey presto, we are equivalent or non-inferior . 

Practically significant change, equivalence and non-inferiority testing... 

Numerous methods to measure the biodegradability of polymers have been developed. Because of slightly different definitions or interpretation of the term biodegradability , the different approaches are therefore not equivalent in terms of information they provide or the practical significance. Since the typical exposure environment involves incubation of a polymer substrate with microorganisms or enzymes, only a limited number of measurements are possible. These include those pertaining to the substrates, to the microorganisms, or to the reactive products. 

The steady-state characteristics of practical significance for a lean-burning jet combustor intended to control pollutant emissions are its lean operating limits for eflBcient, stable combustion i.e., the minimum operating equivalence ratios that yield acceptable levels of CO and un-bumed HC emissions. Those operating points that also yield acceptable... 

In assessing the efficacy of in vitro versus in vivo production of reagent antibody, consideration must be given both to the relative concentrations of antibody and to the volumes obtainable. Subcutaneous inoculation of cells in a mouse yields approximately 1 ml of serum 2 weeks later the yield of ascitic fluid harvested 7-14 days after intraperitoneal injection is between 5 and 15 ml. As the concentration of antibody produced in this way is at least 100-fold greater than in tissue culture, 10 ml of ascitic fluid from one mouse would be equivalent to at least 1 liter of tissue culture fluid. In this context, the recent description of hybridomas produced by fusion of a rat myeloma line with rat spleen cells is likely to be of considerable practical significance because of the larger volume of serum obtainable following inoculation of hybridomas in these rodents. ... 

The total radioactive material inventory simultaneously in-process within the Zone 2A canyon is limited to the equivalent of six maximally irradiated targets to ensure that a dose of 2.0 rem at 3000 meters is not exceeded in the most bounding radiological accident scenario (unmitigated fire). The amounts of radioactive material permitted in operable glove boxes and fume hoods are negligible compared to the SCBs, and are administratively controlled to be consistent with prudent Health Physics practices. Significant amounts shall be addressed in detailed procedures that are reviewed and approved by the RCSC. 

Summarizing, then, the surface-volume mean may be calculated as the arithmetic mean of the surface distribution or the harmonic mean of the volume distribution. The practical significance of the equivalence of means is that it permits useful means to be calculated easily from a single size analysis. 

The conditions for V = Vm, at which the velocities of the oxide and metal surface are equal and a planar reaction interface, this represents a special case. The cooperative or coupled growth of pores and metal in metal oxide reduction systems is equivalent eutectic and eutectoid reactions encountered in solidification and solid state fransfoimalions in which a single phase decomposes into two or more phases [18]. The coupled growth of pores and metal is of particular practical significance since in this situation both the original oxide and metal surfaces remain exposed to the gas throughout the reaction. 

A downside to the buyback clause (or any equivalent practice, such as holding-cost subsidy or price support) is that it leads to surplus inventory that must be salvaged or disposed. The task of returning unsold product increases supply chain costs. The cost of returns can be eliminated if the manufacturer gives the retailer a markdown allowance and allows it to sell the product at a significant discount. Publishers today generally do not ask retailers to return unsold books instead, they give a markdown allowance for them. Retailers then mark them down and sell them for a considerable discount. 

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