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Robin John Hyndman (born 2 May 1967 [citation needed]) is an Australian statistician known for his work on forecasting and time series. He is a Professor of Statistics at Monash University [ 1 ] and was Editor-in-Chief of the International Journal of Forecasting from 2005–2018. [ 2 ]
The elements of a dispersion fan diagram [1] are: a circular line as scale; a diameter which indicates the median; a fan (a segment of a circle) which indicates the quartiles; two feathers which indicate the extreme values. The scale on the circular line begins at the left with the starting value (e. g. with zero). The following values are ...
Download as PDF; Printable version; In other projects Wikidata item; ... [3] Scale invariance: ... while the "symmetric" sMAPE and sMdAPE [4] fail the second criterion.
Percentile ranks are not on an equal-interval scale; that is, the difference between any two scores is not the same as between any other two scores whose difference in percentile ranks is the same. For example, 50 − 25 = 25 is not the same distance as 60 − 35 = 25 because of the bell-curve shape of the distribution. Some percentile ranks ...
In the empirical sciences, the so-called three-sigma rule of thumb (or 3 σ rule) expresses a conventional heuristic that nearly all values are taken to lie within three standard deviations of the mean, and thus it is empirically useful to treat 99.7% probability as near certainty.
The 25th percentile is also known as the first quartile (Q 1), the 50th percentile as the median or second quartile (Q 2), and the 75th percentile as the third quartile (Q 3). For example, the 50th percentile (median) is the score below (or at or below, depending on the definition) which 50% of the scores in the distribution are found.
For instance, the 10% trimmed mean is the average of the 5th to 95th percentile of the data, while the 90% winsorized mean sets the bottom 5% to the 5th percentile, the top 5% to the 95th percentile, and then averages the data. Winsorizing thus does not change the total number of values in the data set, N.
With a norm-referenced test, grade level was traditionally set at the level set by the middle 50 percent of scores. [10] By contrast, the National Children's Reading Foundation believes that it is essential to assure that virtually all children read at or above grade level by third grade, a goal which cannot be achieved with a norm-referenced ...