Cumulative percentage

The cumulative percentage points can be plotted on a distorted %-axis (so-called normal probability scale ) that yields a straight line for perfectly ND data. 

FIGURE 1 Rate of polyanhydride degradation versus time. PCPP and SA copolymers were formulated into 1.4-cm-diameter disks 1 mm thick by compression molding, and placed into a 0.1 M pH 7.4 phosphate buffer solution at 37°C. The cumulative percentage of the polymer which degraded was measured by absorbance at 250 nm. 

Fig. 36.7. Percentage variance of X-content explained by the principal components from spectral data. Individual percentages (bars) are shown as well as cumulative percentages (circles).

Fig. 11 Sieving data presented as a cumulative percentage undersize plot. The data were used to determine the geometric mean diameter of ethylcellulose microcapsules. (Adapted from Ref. 19.)...

FIGURE 10.2. Dose-response is plotted in terms of the probit of cumulative percentage response to logarithm of the exposure concentrations. 

Calculate the percentage of each particle size range retained in the sand sample. Also report the cumulative percentages. 

Solution These cumulative percentages are of the same form as in Figure 2.5 therefore, the particle size distribution peaks where the cumulative curve increases most steeply. This occurs at about 0.29 for this distribution. Equation (10) permits the sedimentation velocity for particles of this size to be calculated ... 

Fig. 2. Cumulative percentage of -16.0 mm fines vs. number of drops of five types of cushioning tests of South Blackwater coal on steel surface.

Number of drops Cumulative percentage of —16.0 mm fines of South Blackwater coal... 

Figure 6.6 shows a generalized dose-response curve. Such a plot may be obtained, for example, by administering different doses of a poison in a uniform manner to a homogeneous population of test animals and plotting the cumulative percentage of deaths as a function of the log of the dose. The result is normally an S-shaped curve, as shown in Figure 6.6. The dose corresponding to the midpoint (inflection point) of such a curve is the statistical estimate of the dose that would cause death in 50% of the subjects and is designated as LD50. The estimated doses at which 5% (LD5)...

Particle Diameter ( xm) Mass Distribution (mg) Number Distribution Percentage of Dose for One Particle Cumulative Percentage of Dose... 

Figure 19 Worked example El cumulative percentage under size versus particle size...

By this method the number of particles per traverse was calculated. The average number of particles in each size interval was progressively cumulated and the cumulated percentage of particles in each size interval was then calculated for making plots, size versus normalized cumulative percent on log probability graph paper. 

The cumulative percentage eigenvalue is often used to determine (approximately) what proportion of die data has been modelled using PCA and is given by Y. =lga. The closer to 100 %, die more faithful is die model. The percentage can be plotted against the number of eigenvalues in die PC model. 

---