Randomize a Series

 

Menu location: Analysis_Randomization_Series X to Y

 

This function randomizes a series of integers for which you define the beginning and end points of the series.

 

For example, randomizing numbers from 6 to 10 is like shuffling 5 cards labelled 6 to 10. To randomize a series of 49 possible lottery numbers enter x as 1 and y as 49:

 

Random allocation of numbers in a series

Randomized with seed: 10
1 43
2 17
3 14
4 31
5 34
6 40
7 41
8 42
9 16
10 2
11 37
12 7
13 19
14 11
15 30
16 48
17 13
18 25
19 46
20 4
21 18
22 28
23 12
24 32
25 49
26 22
27 36
28 45
29 44
30 5
31 3
32 39
33 6
34 10
35 27
36 26
37 8
38 47
39 9
40 24
41 21
42 35
43 33
44 20
45 29
46 23
47 1
48 15
49 38

 

You could then take the first, say six, as your random selection.

 

The seed is printed with the series so that the series can be produced again: enter 10 as the seed to repeat the series above.

 

Technical validation

Robust (pseudo-)random number generation is used, see random number generation.

This R code reproduces the illustration above, with the different series that R's own generator gives for the same seed. It needs no packages and was checked with R 4.6.1. Paste it into R, or save it as a script and run it.

# Randomizing a series of integers: the StatsDirect help illustration (the numbers
# 1 to 49, as in a lottery, put in a random order with seed 10) in R
x <- 1
y <- 49
seed <- 10

# sample(x:y) returns the integers x to y in a random order, every order being
# equally likely. StatsDirect and R each have their own Mersenne Twister generator
# and their own way of turning its output into a random order, so the same seed
# gives a different series in R: the two columns of the output are the same, the
# numbers are not. Keep the seed with the series, as either program can then repeat it.
# (For a series of one number, x = y, sample(x:y) would instead shuffle 1 to x.)
set.seed(seed)
series <- sample(x:y)
cat("Random allocation of numbers in a series\n")
cat("Randomized with seed:", seed, "\n")
print(data.frame(position = seq_along(series), number = series), row.names = FALSE)

# Six lottery numbers: the first six of the series, or equivalently sample(x:y, 6),
# which draws six of the numbers without replacement
cat("The first six:", head(series, 6), "\n")

# The five cards labelled 6 to 10
set.seed(seed)
cat("Cards 6 to 10 shuffled:", sample(6:10), "\n")