density

Examples of density in the following topics:

• Density-Dependent and Density-Independent Population Regulation

  • Population regulation is a density-dependent process, meaning that population growth rates are regulated by the density of a population.
  • In population ecology, density-dependent processes occur when population growth rates are regulated by the density of a population.
  • In addition, low prey density increases the mortality of its predator because it has more difficulty locating its food source.
  • Its chances of survival are the same whether the population density is high or low.
  • In this population of roundworms, fecundity (number of eggs) decreases with population density.

• The Density Scale

  • Density estimation is the construction of an estimate based on observed data of an unobservable, underlying probability density function.
  • Histograms are used to plot the density of data, and are often a useful tool for density estimation.
  • Density estimation is the construction of an estimate based on observed data of an unobservable, underlying probability density function.
  • The unobservable density function is thought of as the density according to which a large population is distributed.
  • A probability density function, or density of a continuous random variable, is a function that describes the relative likelihood for this random variable to take on a given value.

• Density

  • Network>Cohesion>Density is a useful tool for calculating the density of whole populations, or of partitions.
  • Partitioning is not necessary to calculate density.
  • Next, the within-block densities are presented.
  • The density in the 1,1 block is .6667.
  • A social structure in which individuals were highly clustered would display a pattern of high densities on the diagonal, and low densities elsewhere.

• Hypotheses about two paired means or densities

  • In the section above on univariate statistics for networks, we noted that the density of the information exchange matrix for the Knoke bureaucracies appeared to be higher than the density of the monetary exchange matrix.
  • That is, the mean or density of one relation among a set of actors appears to be different from the mean or density of another relation among the same actors.
  • Network>Compare densities>Paired (same node) compares the densities of two relations for the same actors, and calculates estimated standard errors to test differences by bootstrap methods.
  • The difference between means (or proportions, or densities) is .3000.
  • So, we can conclude with great confidence that the density of information ties among organizations is greater than the density of monetary ties.

• Volume and Density

  • Density is another measurement derived from SI basic units.
  • Density is calculated by the dividing the mass by the volume, so that density is measured as units of mass/volume, often g/mL.
  • Different substances have different densities, so density is often used as a method to identify a material.
  • An object with a higher density will sink.
  • At that point, the density trend reverses.

• Density Calculations

  • A reformulation of the Ideal Gas Equation involving density allows us to evaluate the behaviors of ideal gases of unknown quantity.
  • Now, recall that density is equal to mass divided by volume:
  • We can substitute in density, D, and get the following:
  • This derivation of the Ideal Gas Equation allows us to characterize the relationship between the pressure, density, and temperature of the gas sample independent of the volume the gas occupies; it also allows us to determine the density of a gas sample given its pressure and temperature, or determine the molar mass of a gas sample given its density.
  • Atmospheric science offers one plausible real-life application of the density form of the ideal gas equation.

• Probability

  • Probability density function describes the relative likelihood, or probability, that a given variable will take on a value.
  • In probability theory, a probability density function (pdf), or density of a continuous random variable, is a function that describes the relative likelihood for this random variable to take on a given value.
  • The probability for the random variable to fall within a particular region is given by the integral of this variable's probability density over the region.
  • The probability density function is nonnegative everywhere, and its integral over the entire space is equal to one.
  • A probability density function is most commonly associated with absolutely continuous univariate distributions.

• Continuous Probability Distributions

  • A continuous probability distribution is a probability distribution that has a probability density function.
  • The probability density function is nonnegative everywhere, and its integral over the entire space is equal to one.
  • Unlike a probability, a probability density function can take on values greater than one.
  • The standard normal distribution has probability density function:
  • Boxplot and probability density function of a normal distribution $$$N(0, 2)$.

• Flotation

  • Density plays a crucial role in Archimedes' principle.
  • where $\bar{\rho}_\mathrm{obj}$ is the average density of the object and $\rho_\mathrm{fl}$is the density of the fluid.
  • Note that it mentions the average density of the object.
  • This can be much less than the density of the material the object is made of.
  • This formula makes sense only if the density of the object is smaller than the density of the fluid.

• Density

  • The density of a binary network is simply the proportion of all possible ties that are actually present.
  • Network>Cohesion>Density is a quite powerful tool for calculating densities.
  • To obtain densities for a matrix (as we are doing in this example), we simply need a dataset.
  • The Network>Cohesion>Density algorithm also can be used to calculate the densities within partitions or blocks by specifying the file name of an attribute data set that contains the node name and partition number.
  • That is, the density tool can be used to calculate within and between block densities for data that are grouped.