data

Data

Methods

boxplot

(static) boxplot(sortedData, coeffopt, accessoropt) → {object}

Performs complete boxplot analysis including computation of notches and outliers.

Example
var data = [
  -12, 14, 14, 14, 16, 18, 20, 20, 21, 23, 27, 27, 27, 29, 31,
  31, 32, 32, 34, 36, 40, 40, 40, 40, 40, 42, 51, 56, 60, 88
];
boxplot( data );
returns {
//   min: -12, q1: 20, median: 31, q3: 40, max: 88,
//   iqr: 20, range: 100, size: 30,
//   leftOutliers: { begin: 0, end: 0, count: 1, fence: 14 },
//   rightOutliers: { begin: 29, end: 29, count: 1, fence: 60 },
//   leftNotch: 25.230655727612252,
//   rightNotch: 36.76934427238775
// }
Parameters
Name Type Attributes Default Description
sortedData array

sorted in ascending order of value.

coeff number <optional>
1.5

used for outliers computation.

accessor string number function <optional>

required when elements of sortedData are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

consisting of min, q1, median, q3, max, iqr, range, size along with leftNotch, and rightNotch. The leftOutliers/rightOutliers (object), if present, contains the count, fence and begin/end indexes to sortedData for easy extraction of exact values.

Type
object

fiveNumSummary

(static) fiveNumSummary(sortedData, accessoropt) → {number}

Returns the five number summary from the sortedData.

Example
fiveNumSummary( [ 1, 1, 2, 2, 3, 3, 4, 4 ] );
// returns {
//   q1: 1.25, median: 2.5, q3: 3.75, iqr: 2.5,
//   size: 8, min: 1, max: 4, range: 3
// }
Parameters
Name Type Attributes Description
sortedData array

sorted in ascending order of value.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

5-number summary consisting of min, q1, median, q3, max along with iqr, range, and size.

Type
number

histogram

(static) histogram(sortedData, dataPrecisionopt, accessoropt) → {object}

Generates histogram using Freedman–Diaconis method. If both IQR and MAD are 0 then it automatically switches to Sturges' Rule while ensuring minimum of 5 bins. It attempts to reduce excessive sparsity of distribution, if any, by adjusting the number of bins using Sturges' Rule.

Example
var data = [
  12, 14, 14, 14, 16, 18, 20, 20, 21, 23, 27, 27, 27, 29, 31,
  31, 32, 32, 34, 36, 40, 40, 40, 40, 40, 42, 51, 56, 60, 65
];
histogram( data );
// returns {
//   classes: [
//     { min: 12, mid: 19, max: 25 },
//     { min: 25, mid: 32, max: 38 },
//     { min: 38, mid: 45, max: 51 },
//     { min: 51, mid: 58, max: 64 },
//     { min: 64, mid: 71, max: 77 } ],
//   frequencies: [ 10, 10, 7, 2, 1 ],
//   q1: 20,  q3: 40, iqr: 20, size: 30, min: 12, max: 65,range: 53
// }
Parameters
Name Type Attributes Default Description
sortedData array

sorted in ascending order of value.

dataPrecision number <optional>
0

typically the minumum number of decimal places observed in the sortedData.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

conatining arrays classes and the corresponding frequencies. Each element of classes array is an object with values for min/max (class intervals) and mid point of a class.

In addition, the returned object contains useful statistics like q1, q3, iqr, min, max, and range.

Type
object

mad

(static) mad(sortedData, accessoropt) → {number}

Returns the median of the sortedData.

Example
mad( [ 1, 1, 2, 2, 3, 3, 4, 4 ] );
// returns 1
Parameters
Name Type Attributes Description
sortedData array

sorted in ascending order of value.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

median of the sortedData.

Type
number

max

(static) max(x, accessoropt) → {object}

Finds the maximum value in the x array.

Example
max( [ 99, 1, -1, +222, 0, -99 ] )
// returns 222
max( [ { x: 33 }, { x: 11 }, { x:44 } ], 'x' )
// returns 44
Parameters
Name Type Attributes Description
x array

array containing 1 or more elements.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

maximum value from array x.

Type
object

mean

(static) mean(x, accessoropt) → {number}

Comuptes the mean of numbers contained in the x array. The computations are inspired by the method proposed by B. P. Welford.

Example
mean( [ 2, 3, 5, 7 ] )
// returns 4.25
mean( [ { x: 2 }, { x: 3 }, { x: 5 }, { x: 7 } ], 'x' )
// returns 4.25
Parameters
Name Type Attributes Description
x array

array containing 1 or more elements.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

mean value.

Type
number

median

(static) median(sortedData, accessoropt) → {number}

Returns the median of the sortedData.

Example
median( [ 1, 1, 2, 2, 3, 3, 4, 4 ] );
// returns 2.5
Parameters
Name Type Attributes Description
sortedData array

sorted in ascending order of value.

accessor string number function <optional>

Useful when each element of sortedData is an object or an array instead of number. If it is an object then it should be the key (string) to access the value; or if it is an array then it should be the index (number) to access the value; or it should be a function that extracts the value from the element passed to it.

Returns

median of the sortedData.

Type
number

min

(static) min(x, accessoropt) → {object}

Finds the minimum value in the x array.

Example
min( [ 99, 1, -1, +222, 0, -99 ] )
// returns -99
min( [ { x: 33 }, { x: 11 }, { x:44 } ], 'x' )
// returns 11
Parameters
Name Type Attributes Description
x array

array containing 1 or more elements.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

minimum value from array x.

Type
object

percentile

(static) percentile(sortedData, q, accessoropt) → {number}

Returns the qth percentile from the sortedData. The computation is based on Method 11 described in Quartiles in Elementary Statistics by Eric Langford published in Journal of Statistics Education Volume 14, Number 3 (2006).

Example
percentile( [ 1, 1, 2, 2, 3, 3, 4, 4 ], 0.25 );
// returns 1.25
percentile( [ 1, 1, 2, 2, 3, 3, 4, 4 ], 0.75 );
// returns 3.75
Parameters
Name Type Attributes Description
sortedData array

sorted in ascending order of value.

q number

should be between 0 and 1 indicating percentile; for example, to get 25th percentile, it should be 0.25.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

qth percentile of sortedData.

Type
number

stdev

(static) stdev(x, accessoropt) → {number}

Comuptes the sample standard deviation of numbers contained in the x array. The computations are inspired by the method proposed by B. P. Welford.

Example
stdev( [ 2, 3, 5, 7 ] )
// returns 2.217355782608345
stdev( [ { x: 2 }, { x: 3 }, { x: 5 }, { x: 7 } ], 'x' )
// returns 2.217355782608345
Parameters
Name Type Attributes Description
x array

array containing 1 or more elements.

accessor string number function <optional>

required when elements of x are objects or arrays instead of numbers. For objects, use key (string) to access the value; in case of arrays, use index (number) to access the value; or it could be a function that extracts the value from the element passed to it.

Returns

standard deviation of sample.

Type
number