Percentile in the context of "Decile"

In statistics and probability, quantiles are cut points dividing the range of a probability distribution into continuous intervals with equal probabilities or dividing the observations in a sample in the same way. There is one fewer quantile than the number of groups created. Common quantiles have special names, such as quartiles (four groups), deciles (ten groups), and percentiles (100 groups). The groups created are termed halves, thirds, quarters, etc., though sometimes the terms for the quantile are used for the groups created, rather than for the cut points.

q-quantiles are values that partition a finite set of values into q subsets of (nearly) equal sizes. There are q − 1 partitions of the q-quantiles, one for each integer k satisfying 0 < k < q. In some cases the value of a quantile may not be uniquely determined, as can be the case for the median (2-quantile) of a uniform probability distribution on a set of even size. Quantiles can also be applied to continuous distributions, providing a way to generalize rank statistics to continuous variables (see percentile rank). When the cumulative distribution function of a random variable is known, the q-quantiles are the application of the quantile function (the inverse function of the cumulative distribution function) to the values {1/q, 2/q, …, (q − 1)/q}.

Mensa International is the largest and oldest high-IQ society in the world. It is a non-profit organization open to people who score at the 98th percentile or higher on a standardised, supervised IQ or other approved intelligence test. Mensa formally comprises national groups and the umbrella organisation Mensa International, with a registered office in Caythorpe, Lincolnshire, England, which is separate from the British Mensa office in Wolverhampton.

Reading comprehension is the ability to process written text, understand its meaning, and to integrate with what the reader already knows. Reading comprehension relies on two abilities that are connected to each other: word reading and language comprehension. Comprehension specifically is a "creative, multifaceted process" that is dependent upon four language skills: phonology, syntax, semantics, and pragmatics. Reading comprehension is beyond basic literacy alone, which is the ability to decipher characters and words at all. The opposite of reading comprehension is called functional illiteracy. Reading comprehension occurs on a gradient or spectrum, rather than being yes/no (all-or-nothing). In education it is measured in standardized tests that report which percentile a reader's ability falls into, as compared with other readers' ability.

Some of the fundamental skills required in efficient reading comprehension are the ability to:

In statistics, quartiles are a type of quantiles which divide the number of data points into four parts, or quarters, of more-or-less equal size. The data must be ordered from smallest to largest to compute quartiles; as such, quartiles are a form of order statistic. The three quartiles, resulting in four data divisions, are as follows:

Along with the minimum and maximum of the data (which are also quartiles), the three quartiles described above provide a five-number summary of the data. This summary is important in statistics because it provides information about both the center and the spread of the data. Knowing the lower and upper quartile provides information on how big the spread is and if the dataset is skewed toward one side. Since quartiles divide the number of data points evenly, the range is generally not the same between adjacent quartiles (i.e. usually (Q₃ - Q₂) ≠ (Q₂ - Q₁)). Interquartile range (IQR) is defined as the difference between the 75th and 25th percentiles or Q₃ - Q₁. While the maximum and minimum also show the spread of the data, the upper and lower quartiles can provide more detailed information on the location of specific data points, the presence of outliers in the data, and the difference in spread between the middle 50% of the data and the outer data points.

In probability and statistics, a probability distribution's quantile function is the inverse of its cumulative distribution function. That is, the quantile function of a distribution ${\displaystyle {\mathcal {D}}}$ is the function ${\displaystyle Q}$ such that ${\displaystyle \Pr \left[\mathrm {X} \leq Q(p)\right]=p}$ for any random variable ${\displaystyle \mathrm {X} \sim {\mathcal {D}}}$ and probability ${\displaystyle p\in [0,1]}$.

The quantile function is also called the percentile function (after the percentile), percent-point function, inverse cumulative distribution function or inverse distribution function.

A growth chart is used by pediatricians and other health care providers to follow a child's growth with age. Growth charts have been constructed by observing the growth of large numbers of healthy children over time. The height, weight, and head circumference of a child can be compared to the expected parameters of children of the same age and sex to determine whether the child is growing appropriately. For each parameter, a set of growth curves are graphed for the median value (the "middle" value, at 50 percentile), lower and upper quartiles (bottom and top 25%), as well the lower and upper deciles (bottom and top 10%).

Growth charts can also be used to predict the expected adult height and weight of a child because, in general, children maintain a fairly constant growth curve. When a child deviates from his or her previously established growth curve, investigation into the cause is generally warranted. Parameters used to analyze growth charts include weight velocity (defined as rate of change in weight over time), height velocity (defined as rate of change in stature over time), and whether someone's growth chart crosses percentiles. For instance, endocrine disorders can be associated with a decrease in height velocity and preserved weight velocity while normal growth variants are associated with a decrease in height and weight velocity that are proportional to each other. It's important to note that other parameters are more commonly used such as waist circumference for assessing obesity and skin fold difference for assessing malnutrition. Growth charts can also be compiled with a portion of the population deemed to have been raised in more or less ideal environments, such as nutrition that conforms to pediatric guidelines, and no maternal smoking. Charts from these sources end up with slightly taller but thinner averages.