Search results
Results From The WOW.Com Content Network
If a data distribution is approximately normal then about 68 percent of the data values are within one standard deviation of the mean (mathematically, μ ± σ, where μ is the arithmetic mean), about 95 percent are within two standard deviations (μ ± 2σ), and about 99.7 percent lie within three standard deviations (μ ± 3σ).
In toxicology, the median lethal dose, LD 50 (abbreviation for "lethal dose, 50%"), LC 50 (lethal concentration, 50%) or LCt 50 is a toxic unit that measures the lethal dose of a given substance. [1] The value of LD 50 for a substance is the dose required to kill half the members of a tested population after a specified test duration.
Thus, a 60% duty cycle means the signal is on 60% of the time but off 40% of the time. The "on time" for a 60% duty cycle could be a fraction of a second, a day, or even a week, depending on the length of the period.
Each row of points is a sample from the same normal distribution. The colored lines are 50% confidence intervals for the mean, μ. At the center of each interval is the sample mean, marked with a diamond. The blue intervals contain the population mean, and the red ones do not.
This follows from the fact that the variance and mean are independent of the ordering of x. Scale invariance: c v (x) = c v (αx) where α is a real number. [22] Population independence – If {x,x} is the list x appended to itself, then c v ({x,x}) = c v (x). This follows from the fact that the variance and mean both obey this principle.
The crude death rate is defined as "the mortality rate from all causes of death for a population," calculated as the "total number of deaths during a given time interval" divided by the "mid-interval population", per 1,000 or 100,000; for instance, the population of the U.S. was around 290,810,000 in 2003, and in that year, approximately 2,419,900 deaths occurred in total, giving a crude death ...
Absolute humidity is the total mass of water vapor present in a given volume or mass of air. It does not take temperature into consideration. Absolute humidity in the atmosphere ranges from near zero to roughly 30 g (1.1 oz) per cubic metre when the air is saturated at 30 °C (86 °F).
Active membership varied from a high of 40 to 50 percent in congregations in North America and the Pacific Islands, to a low of about 25 percent in Latin America. Fletcher Stack's data was compiled from several sources, including a 2001 survey of religious affiliation by scholars at City University of New York and a demographer at LDS-owned ...