Complete the following steps to specify the data for your analysis.

- In Variables, enter the columns that contain the sample data. Minitab performs separate tolerance interval analyses on each column that you enter.
- From Distribution, select the distribution that the data follow. For more information on a distribution, go to Distributions for Tolerance Intervals (Nonnormal distribution).
- Lognormal - Use when the logarithm of the random variable is normally distributed.
- Gamma - Use to model positive data values that are skewed to the right.
- Exponential - Use to model the time between events in a homogeneous Poisson process.
- Smallest extreme value - Use to model data values that are skewed to the left. The smallest extreme value distribution is the distribution of the minimum of a large number of random variables from a specific group of distributions. It's often used to model the logarithm of failure times.
- Weibull - Usually used to describe failure distributions. It can also be used to model the minimum of a large number of positive random variables from a specific group of distributions.
- Largest extreme value - Use to model data values that are skewed to the right. It's usually used to describe the maximum of a large number of random variables from a specific group of distributions.
- Logistic - Use to model distributions that have a similar shape to the normal distribution, but with longer tails.
- Loglogistic - Use when the logarithm of the variable is logistically distributed.
- Assume none - Use when you are not willing to make any assumption about the population of your data. Minitab only displays results for the nonparametric method. However, a large sample is usually required for the result to be accurate.

- In Minimum percentage of population in interval, enter the minimum percentage of the population that you want a two-sided tolerance interval to include, or a one-sided lower limit to be less than or a one-sided upper limit to be greater than.

In this worksheet, Brightness contains the sample data.

C1 |
---|

Brightness |

81.50 |

78.80 |

79.55 |

83.02 |

80.26 |

86.50 |

84.76 |

76.74 |