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Distribution Analyses |

The options you set in this dialog determine which tables and graphs appear in the distribution window. A distribution analysis can include descriptive statistics, graphs, density estimates, and cumulative distribution function estimates. By default, SAS/INSIGHT software displays a moments table, a quantiles tables, a box plot, and a histogram. Individual tables and graphs are described following this section.

You can specify the coefficient in the **Parameters:Alpha:**
entry field. The confidence level is used in
the basic confidence intervals and the trimmed/Winsorized means tables.
You can specify in the **Parameters: Mu0:**
entry field. is used in the tests for location and
the trimmed/Winsorized means tables.
You can also specify in the **Parameters: Theta:** entry field.
The parameter is used in the parametric density estimation
and cumulative distribution for lognormal, exponential,
and Weibull distributions.

If you select a **Weight** variable, tables of weighted moments,
weighted quantiles, weighted confidence intervals, weighted tests
for location, and weighted frequency counts can be generated.
Robust measures of scale, tests for normality, and
trimmed/Winsorized means are not computed.
Graphs of weighted box plot, weighted histogram, and
weighted normal QQ plot can also be generated.

The **Trimmed/Winsorized Means** button enables you to view or
change the options associated with trimmed and Winsorized means.
Click on **Trimmed/Winsorized Means** to display
the **Trimmed/Winsorized Means** dialog.

In the dialog, you choose the number of observations
trimmed or Winsorized in each tail in (1/2)N
and the percent of observations trimmed or Winsorized
in each tail in (1/2)Percent.
If you specify a percentage,
the smallest integer greater than or equal to *np*
is trimmed or Winsorized.

The **Density Estimation** button enables you to set
the options associated with both parametric density
and nonparametric kernel density estimation.
Click on **Density Estimation** to display
the **Density Estimation** dialog.

If you select **Parametric Estimation:Normal**, a normal distribution
with the sample mean and standard deviation is created.
For the lognormal, exponential, and Weibull distributions,
you specify the threshold parameter in the
**Parameters:Theta:** entry field in the distribution output options
dialog, as shown in Figure 38.4,
and have the remaining parameters estimated by
the maximum-likelihood estimates.

If you select a **Weight** variable, the weighted
parametric normal density and weighted kernel density
are generated. The parametric lognormal,
exponential, and Weibull density are not computed.

The **Cumulative Distribution** button enables you to set the
options associated with cumulative distribution estimation.
Click on **Cumulative Distribution** to display
the **Cumulative Distribution**
dialog.

If you select **Fit Parametric:Normal**, a normal distribution
with the sample mean and standard deviation is created.
For the lognormal, exponential, and Weibull distributions,
you specify the threshold parameter in the
**Parameters:Theta:** entry field in the distribution output options
dialog, as shown in Figure 38.4,
and have the remaining parameters estimated by
the maximum-likelihood estimates.

If you select a **Weight** variable, weighted empirical
and normal cumulative distribution functions can be generated.
The confidence bands, the parametric lognormal,
exponential, and Weibull cumulative distributions,
and tests for distribution are not computed.

Click on **OK** to close the dialogs and
create your distribution analysis.

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