Use the random number generation tool to generate random
numbers. This tool can generate random numbers from various
probability distributions.
Specify the number of variables in
the "Number of Variables:" entry. This determines the
number of columns of random values to be produced.
Specify the number of random numbers for each variable in the
"Size of Sample:" entry. This determines the number
of rows of random values to be produced.
Specify the
random distribution by selecting one of the items from the
random distribution list. The following random distributions are
supported: Discrete, Normal, Poisson, Exponential, Binomial,
Negative Binomial, Bernoulli, and Uniform.
Specify the parameters of the selected distribution:
Discrete Random Distribution
Specify the value and
probability input range in the "Value and Probability Input
Range:" entry box. The value and
probability input range is a table consisting of two columns
and any number of rows. The first column specifies the
discrete random values and the second column the probabilities
for them. The discrete random values do not have to be
numbers, for example, strings will do as well. The sum of the
probabilities in the second column should be one. For
example, if you have the values A, B, C, and D in A1:A4 and
values 0.1, 0.4, 0.2, and 0.3 in B1:B4, you would specify the
value and probability input range to be A1:B4.
If the probabilities do not add to 1, they will be
automatically scaled.
Normal Random Distribution
Specify the mean and the
standard deviation. The default values are 0 for the
mean and 1 for the standard deviation.
Poisson Random Distribution
Specify the lambda in
the "Lambda" entry. Lambda is the average
number of events in a unit time interval.
Exponential Random Distribution
Specify b in
the "b Value" entry.
Binomial Random Distribution
Specify the
probability of success (p) in the
"p Value" entry and the
number of trials (n) in the
"Number of Trials" entry.
The Binomial
distribution is a discrete distribution in which the
experiment consists of n identical trials.
Each trial is independent of other the trials
and has two possible outcomes, a success or a failure. The
probability of success p is constant from
one trial to another.
The mean of a random variable that has a Binomial distribution
is E(X) = np, and the variance is
var(X) = np(1-p).
Negative Binomial Distribution
Specify the
probability of success p in the
"p Value" entry and the
number of failures r in the
"Number of Failures" entry.
Negative Binomial distribution is a discrete distribution in
which the experiment consists of a sequence of independent
trials. Each trial has two possible outcomes, a success or a
failure. The probability of success p
is constant from one trial to another. The experiment continues
until r failures
are observed, where r is fixed in advance. The mean of a
random variable that has a Negative Binomial distribution is
E(X) = r(1-p)/p, and the variance is var(X) =
r(1-p)/p^2.
Bernoulli Random Distribution
Specify the probability of success (p) in the
"p Value" entry. p
is a probability value between 0 and 1. The
Bernoulli distribution has two random values 0 and 1, and
p is the probability to observe value 1. The mean of
a random variable that has a Bernoulli distribution is E(X) =
1(p) + 0(1-p) = p, and the variance is var(X) =
p(1-p).
Uniform Random Distribution
Specify the range of
the continuous random variable with the "Between:"
and "And:"
entries. The default values for these entries are 0 and 1.