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Statistics
mean stdev Stdev max min hist histogram var Var median mode gmean hmean skew kurt cvar corr
mean(A, …) As in Mathcad
The average of all the elements.
Takes numbers, vectors and matrices, any mix, and averages every element. See also stdev, var and median.
Units
The answer is in the units of the first element.
Refused
- Elements that aren't numbers.
mean⎝⎛⎝⎛126⎠⎞⎠⎞=3
mean(2,4,9)=5
stdev(A, …) As in Mathcad
The population standard deviation of all the elements: the root of the mean squared distance from the mean.
Divides by n, the number of elements. Stdev divides by n − 1 instead, for a sample. See also mean.
Units
The answer is in the units of the first element.
Refused
- Elements that aren't numbers.
stdev⎝⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎛⎝⎜⎜⎜⎜⎜⎜⎜⎜⎜⎜⎛24445579⎠⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎞⎠⎟⎟⎟⎟⎟⎟⎟⎟⎟⎟⎞=2
Stdev(A, …) As in Mathcad
The sample standard deviation of all the elements: divides by n − 1.
Use it when the elements are a sample of something larger. stdev divides by n, for the whole population, and so is a little smaller. One element alone gives NaN, as 0 divided by 0.
Units
The answer is in the units of the first element.
Refused
- Elements that aren't numbers.
Stdev⎝⎛⎝⎛123⎠⎞⎠⎞=1
stdev⎝⎛⎝⎛123⎠⎞⎠⎞=0.816
max(A, …) As in Mathcad
The largest element.
Takes numbers, vectors and matrices, any mix. See also min.
Units
The elements must be in compatible units; the answer keeps them.
Refused
- No elements.
- Elements in different units.
max⎝⎛⎝⎛394⎠⎞⎠⎞=9
max(2,7,5)=7
min(A, …) As in Mathcad
The smallest element.
Takes numbers, vectors and matrices, any mix. See also max.
Units
The elements must be in compatible units; the answer keeps them.
Refused
- No elements.
- Elements in different units.
min⎝⎛⎝⎛394⎠⎞⎠⎞=3
min(2,7,5)=2
hist(bounds, data) As in Mathcad
A vector of counts: how many data values fall in each interval between consecutive bounds.
bounds is a vector in rising order. Interval i holds the values above bounds[i] up to and including bounds[i+1], so a value on a boundary counts in the interval to its left. Values outside all the intervals are not counted. The answer has one fewer elements than bounds. histogram picks equal intervals for you.
hist⎝⎜⎜⎛⎝⎛024⎠⎞,⎝⎜⎜⎛1234⎠⎟⎟⎞⎠⎟⎟⎞=(22)
histogram(n, data) As in Mathcad
A histogram with n equal intervals spanning the data: a matrix whose first column is each interval's midpoint and second its count.
The intervals run from the smallest value to the largest, and the smallest value counts in the first. A value on a boundary counts in the interval to its left. For intervals you choose, use hist. The two columns plot directly against each other.
Units
The midpoints take the data's units; the counts have none.
Refused
histogram⎝⎜⎜⎛2,⎝⎜⎜⎛1234⎠⎟⎟⎞⎠⎟⎟⎞=(1.753.2522)
var(A, …) As in Mathcad
The variance of all the elements, dividing by their number n: the population variance.
Var divides by n − 1, for a sample. Takes numbers, vectors and matrices, any mix. Its square root is stdev.
Units
In the square of the elements' units.
V≔⎝⎜⎜⎜⎜⎛24459⎠⎟⎟⎟⎟⎞
var(V)=5.36
Var(A, …) As in Mathcad
The sample variance of all the elements, dividing by n − 1.
var divides by n. Its square root is Stdev.
Units
In the square of the elements' units.
Refused
V≔⎝⎜⎜⎜⎜⎛24459⎠⎟⎟⎟⎟⎞
Var(V)=6.7
median(A, …) As in Mathcad
The middle value of all the elements, or the mean of the middle two when there's an even number.
Units
In the elements' units.
median⎝⎜⎜⎛⎝⎜⎜⎛2945⎠⎟⎟⎞⎠⎟⎟⎞=4.5
mode(A, …) As in Mathcad
The value that appears most often among all the elements.
Refused
- No value appearing more than once, or two values tied for most often, as in Mathcad.
mode⎝⎜⎜⎜⎜⎛⎝⎜⎜⎜⎜⎛24459⎠⎟⎟⎟⎟⎞⎠⎟⎟⎟⎟⎞=4
gmean(A, …) As in Mathcad
The geometric mean of all the elements: the nth root of their product.
Refused
hmean(A, …) As in Mathcad
The harmonic mean of all the elements: n over the sum of their reciprocals.
Refused
hmean⎝⎛⎝⎛124⎠⎞⎠⎞=1.714
skew(A, …) As in Mathcad
The sample skewness of all the elements: how lopsided they are, positive when the long tail is above the mean.
n/((n − 1)(n − 2))·Σ((x − mean)/s)³, with s the sample standard deviation, as in Mathcad.
Refused
skew⎝⎜⎜⎜⎜⎛⎝⎜⎜⎜⎜⎛24459⎠⎟⎟⎟⎟⎞⎠⎟⎟⎟⎟⎞=1.228
kurt(A, …) As in Mathcad
The sample kurtosis of all the elements, in excess of a normal distribution's: positive for heavy tails.
Mathcad's formula, with the sample standard deviation and the n − 1, n − 2, n − 3 corrections.
Refused
kurt⎝⎜⎜⎜⎜⎛⎝⎜⎜⎜⎜⎛24459⎠⎟⎟⎟⎟⎞⎠⎟⎟⎟⎟⎞=2.399
cvar(A, B) As in Mathcad
The covariance of two arrays of the same size, dividing by n.
Elements pair up by position. cvar(A, A) is var(A).
Units
In the product of the two arrays' units.
Refused
- Arrays of different sizes.
cvar⎝⎛⎝⎛123⎠⎞,⎝⎛247⎠⎞⎠⎞=1.667
corr(A, B) As in Mathcad
The correlation of two arrays of the same size: from −1 to 1, 1 when one rises in step with the other.
Refused
- Arrays of different sizes.
- An array whose values are all the same.
corr⎝⎛⎝⎛123⎠⎞,⎝⎛247⎠⎞⎠⎞=0.993