Random Number Generator
Use the Random Number Generator to create a list of random numbers,
based on your specifications. The numbers you generate appear in the
Random Number Table.
For help in using the Random Number
Generator, read the
Frequently-Asked Questions
or review the
Sample Problems.
| 100 Random Numbers |
|
56042 60574 00095 54974 63778 90481 83813 50701 76596 25471 25730 78068 94495 18657 72728 10517 70591 16926 51365 01163 51769 73391 61642 96890 64587 08380 77000 97699 09044 01567 23998 56706 85141 99835 02635 20794 66319 56301 12912 16521 79136 91290 28270 43888 23593 84477 75268 76336 73132 82745 53906 66982 80868 12653 64182 62710 93686 74200 79541 63519 11585 67387 26539 22525 87681 65655 05176 86613 68860 95563 15453 82341 81677 57110 57369 09708 26134 50297 04367 42156 02231 48565 83004 06244 83409 78473 66723 01972 96226 40020 08640 29339 40684 33207 55637 88345 90222 31475 34275 52433 Specs: This table of 100 random numbers was produced according to the following specifications: Numbers were randomly selected from within the range of 0 to 99999. Duplicate numbers were allowed. This table was generated on 5/22/2013.
|
Instructions: To find the answer to a frequently-asked
question, simply click on the question.
What are random numbers?
Random numbers are sets of digits (i.e., 0, 1, 2, 3, 4, 5, 6, 7,
8, 9) arranged in random order. Because they are randomly ordered, no
individual digit can be predicted from knowledge of any other digit or group of
digits.
What is a random number generator?
A random number generator is a process that produces
random numbers. Any random process (e.g., a flip of a coin or the toss
of a die) can be used to generate random numbers. Stat Trek's
Random Number Generator uses a statistical algorithm to produce random
numbers.
What is a random number table?
A random number table is a listing of random numbers. Stat Trek's
Random Number Generator produces a listing of random numbers, based on the
following User specifications:
-
The quantity of random numbers desired.
-
The maximum and minimum values of random numbers in the table.
-
Whether or not duplicate random numbers are permitted.
How "random" is Stat Trek's Random Number
Generator?
Although no computer algorithm can produce numbers that are truly
random, Stat Trek's Random Number Generator produces numbers that are nearly
random. Stat Trek's Random Number Generator can be used for most statistical
applications (like randomly assigning subjects to treatments in a statistical
experiment). However, it should not be used to generate numbers for
cryptography.
How can I control the number of entries
in a single random number table?
The value entered in the text box labeled "How many random
numbers" controls the quantity of numbers generated for the random number
table. Stat Trek's Random Number Generator can create up to 1000 random numbers
for a single random number table. If more random numbers are needed, Users can
create additional tables.
What are the minimum and maximum values in
the Random Number Generator?
The minimum and maximum values set limits on the range of values
that might appear in a random number table. The minimum value identifies the
smallest number in the range; and the maximum value identifies the largest
number. For example, if we set the minimum value equal to 12 and the maximum
value equal to 30, the Random Number Generator will produce a table consisting
of random arrangements of the numbers in the range of 12 to 30.
What does it mean to allow duplicate
entries in a random number table?
Stat Trek's Random Number Generator allows Users to permit or
prevent the same number from appearing more than once in the random number
table. To permit duplicate entries, set the drop-down box labeled "Allow
duplicate entries" equal to True. To prevent duplicate entries, change the
setting to False.
Essentially, allowing duplicate entries amounts to
sampling
with replacement;
preventing duplicate entries amounts to
sampling
without replacement.
What is a seed?
The seed is a number that controls whether the Random Number
Generator produces a new set of random numbers or repeats a particular sequence
of random numbers. If the text box labeled "Seed" is blank, the Random Number
Generator will produce a different set of random numbers each time a
random number table is created. On the other hand, if a number is entered in
the "Seed" text box, the Random Number Generator will produce a set of random
numbers based on the value of the Seed. Each time a random number table is
created, the Random Number Generator will produce the same set of
random numbers, until the Seed value is changed.
Note: The ability of the seed to repeat a random
sequence of numbers assumes that other User specifications (i.e., quantity of random
numbers, minimum value, maximum value, whether duplicate values are permitted)
are constant across replications. The use of a seed is illustrated in
Sample Problem 1.
Warning: The seed capability is provided for
Users as a short-term convenience. However, it is not a long-term solution.
From time to time, Stat Trek changes the underlying random number
algorithm to more closely approximate true randomization. A newer
algorithm will not reproduce random numbers generated by an older
algorithm, even with the same seed. Therefore, the safest way to
"save" a random number table is to print it out. The algorithm was last changed
on 1/7/2012.
-
A university is testing the effectiveness of two
different medications. They have 10 volunteers. To conduct the study,
researchers randomly assign a number from 1 to 2 to each volunteer. Volunteers
who are assigned number 1 get Treatment 1 and volunteers who are assigned
number 2 get Treatment 2. To implement this strategy, they input the following
settings in the Random Number Generator:
-
They want to assign a number randomly to each of 10 volunteers, so they need 10
entries in the random number table. Therefore, the researchers enter 10 in the
text box labeled "How many random numbers?".
-
Since each volunteer will receive one of two treatments, they set the minimum
value equal to 1; and the maximum value equal to 2.
-
Since some volunteers will receive the same treatment, the researchers allow
duplicate random numbers in the random number table. Therefore, they set the
"Allow duplicate entries" dropdown box equal to "True".
-
And finally, they set the Seed value equal to 345. (The number 345 is not
special. They could have used any positive integer.)
Then, they hit the Calculate button. The Random Number Generator produces a
Random Number Table consisting of 10 entries, where each entry is the number 1
or 2. The researchers assign the first entry to volunteer number 1, the second
entry to volunteer number 2, and so on.
Using this strategy, what treatment did the first volunteer receive? What
treatment did the tenth volunteer receive?
Solution:
This problem can be solved by recreating the exact Random Number Table used by
the researchers. By inputting all of the same entries (especially the same Seed
value) that were used originally, we can recreate the Random Number Table used
by the researchers. Therefore, we do the following:
-
Enter 10 in the text box labeled "How many random numbers?".
-
Set the minimum value equal to 1 and the maximum value equal to 2.
-
Set the "Allow duplicate entries" dropdown box equal to "True".
-
Set the Seed value equal to 345.
Then, we hit the Calculate button. This produces the Random Number Table shown
below.
| Random Numbers
|
|
2 1 2 1 1 2 1 1 2 2 |
From the table, we can see that the first entry is "2". Therefore, the first
volunteer received Treatment 2. And the second entry is "1". Hence, the second
volunteer received Treatment 1. And so on.
-
We would like to survey 500 families from a population of 20,000 families. Each
family has been assigned a unique number from 1 to 20,000. How can we randomly select
500 families for the survey?
Solution:
We input the following settings in the Random
Number Generator:
-
We want to select 500 families. Therefore, we enter 500 in the text box labeled
"How many random numbers?".
-
Since each family has been assigned a number from 1 to 20,000, we set the
minimum value equal to 1; and the maximum value equal to 20,000.
-
Since we only want to survey each family once, we don't want duplicate random
numbers in our random number table. Therefore, we set the "Allow duplicate
entries" dropdown box equal to "False".
Then, we hit the Calculate button. The Random Number Generator produces a
Random Number Table consisting of 500 unique random numbers between 1 and
20,000. We will survey the families represented by these numbers - a sample of
500 families randomly selected from the population of 20,000 families.