Ex: https://www.hackerrank.com/challenges/s10-basic-statistics
The average of all the integers in a set of values.
Example:
arr = [1, 1, 1, 2, 2, 3, 4, 4]
=> mean = sum(arr)/n = 18/8
weighted mean Given a discrete set of numbers, X, and a corresponding set of weights, W, the weighted mean is calculated as follows: Mw = sum(Xi*Wi)/sum(Wi)
Example:
X = [1, 3, 5], W = [2, 4, 6]
Mw = (1*2 + 2*4 + 5*6) / (2+4+6) = 3.66
Ex: https://www.hackerrank.com/challenges/s10-weighted-mean
The midpoint value of a data set for which an equal number of samples are less than and greater than the value. For an odd sample size, this is the middle element of the sorted sample; for an even sample size, this is the average of the 2 middle elements of the sorted sample.
Example:
arr = [1, 1, 1, 2, 2, 3, 4, 4]
=> median = (2+2)/2 = 2
The element(s) that occur most frequently in a data set.
Example:
arr = [1, 1, 1, 2, 2, 3, 4, 4]
=> mode = 1
The quartiles of an ordered data set are the 3 points that split the data set into 4 equal groups. The 3 quartiles are defined as follows:
- Q1: median number of the first lower half
- Q2: median number of the data set
- Q3: median number of the first upper half
Ex: https://www.hackerrank.com/challenges/s10-quartiles
Interquartile The interquartile range of an array is the difference between its first (Q1) and third (Q3) quartiles (i.e., Q3-Q1).
Ex: https://www.hackerrank.com/challenges/s10-interquartile-range
Ref: https://www.hackerrank.com/challenges/s10-standard-deviation/tutorial
- Variance
- Standard Deviation
Ex: https://www.hackerrank.com/challenges/s10-standard-deviation
Ref: https://www.hackerrank.com/challenges/s10-mcq-1/tutorial
Conditional Probability P(B | A) = P(A intersect B)/P(A) P(B |A) denotes the probability of the occurrence of B given that A has occurred
Bayes' Theorem
Permutation & combination
Ref: http://mathworld.wolfram.com/Permutation.html https://www.hackerrank.com/challenges/s10-mcq-5/tutorial