Probability Functions |
Use these functions to compute and verify statistical measures such as significant probabilities, critical values of statistics, confidence intervals and histogram comparisons. |
Function | Description |
normdist | The cumulative normal (or Gaussian) distribution function. It returns the probability that a normal random variable is less than a specified independent variable value. |
norminv | The inverse cumulative normal (or Gaussian) distribution function. The probability that a normally distributed random variable is less than the return value is equal to the argument you specify. |
normden | The normal (or Gaussian) probability density function. The graph of this function is the familiar ?bell curve?. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
chisquaredist | The cumulative chi-square distribution function. It returns the probability that a chi-square distributed random variable is less than a specified independent variable value. |
chisquareinv | The inverse cumulative chi-square distribution function. The probability that a chi-square distributed random variable is less than the return value is equal to the argument you specify. |
chisquareden | The chi-square probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
fdist | The F-distribution function. It returns the probability that an F distributed random variable is less than a specified independent variable value. |
finv | The inverse F-distribution function. The probability that an F-distributed random variable is less than the return value is equal to the argument you specify. |
fden | The F-distribution?s probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
tdist | The Student?s T-distribution function. It returns the probability that a T-distributed random variable is less than a specified independent variable value. |
tinv | The inverse of Student?s T-distribution function. The probability that a T-distributed random variable is less than the return value is equal to the argument you specify. |
tden | The T-distribution?s probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
gammadist | The cumulative gamma distribution function. It returns the probability that a gamma distributed random variable is less than a specified independent variable value. |
gammainv | The inverse cumulative gamma distribution function. The probability that a gamma distributed random variable is less than the return value is equal to the argument you specify. |
gammaden | The gamma distribution?s probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
weibulldist | The cumulative Weibull distribution function. It returns the probability that a Weibull distributed random variable is less than a specified independent variable value. |
weibullinv | The inverse cumulative Weibull distribution function. The probability that a Weibull distributed random variable is less than the return value is equal to the argument you specify. |
weibullden | The Weibull distribution?s probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
cauchydist | The cumulative Cauchy distribution function. It returns the probability that a Cauchy distributed random variable is less than a specified independent variable value. |
cauchyinv | The inverse cumulative Cauchy distribution function. The probability that a Cauchy distributed random variable is less than the return value is equal to the argument you specify. |
cauchyden | The Cauchy distribution?s probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
erf | The error function. It is related to the cumulative normal distribution function by scaling and translation. |
erfc | The complementary error function. It returns one minus the return value of the error function. |
lognormaldist | The cumulative log-normal distribution function. It returns the probability that a log-normal random variable is less than a specified independent variable value. |
lognormalinv | The inverse cumulative log-normal distribution function. The probability that a log-normal random variable is less than the return value is equal to the argument you specify. |
lognormalden | The log-normal distribution's probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
expdist | The cumulative exponential distribution function. It returns the probability that an exponential random variable is less than a specified independent variable value. |
expinv | The inverse cumulative exponential distribution function. The probability that an exponential random variable is less than the return value is equal to the argument you specify. |
expden | The exponential distribution?s probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
logisdist | The cumulative logistic distribution function. It returns the probability that a logistic random variable is less than a specified independent variable value. |
logisinv | The inverse cumulative logistic distribution function. The probability that a logistic random variable is less than the return value is equal to the argument you specify. |
logisden | The logistic distribution?s probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |
loglogisdist | The cumulative log-logistic distribution function. It returns the probability that a log-logistic random variable is less than a specified independent variable value. |
loglogisinv | The inverse cumulative log-logistic distribution function. The probability that a log-logistic random variable is less than the return value is equal to the argument you specify. |
loglogisden | The log-logistic distribution's probability density function. It returns the value of the slope of the cumulative distribution function at the specified argument value. |