Certification Summary---Producing Descriptive Statistics

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summary

 * Purpose of PROC MEANS:

The MEANS procedure provides an easy way to compute descriptive statistics. Descriptive statistics such as the mean, minimum and maximum provide useful information about numeric data.


 * Specifying Statistics:

By default, PROC MEANS computes the n-count(the number of nonmissing values), the mean, the standard deviation, and the minimum and maximum values for variables. To specify statistics, list their keywords in the PROC MEANS statement.


 * Limiting Decimal Places:

Use the MAXDEC=option and set it equal to the length that you prefer.


 * Specifying Variables in PROC MEANS:

By default, PROC MEANS computes statistics for all numeric variables. To specify the variables to include in PROC MEANS output, list them in a VAR statement.


 * Creating n-way Tables:

Crosstabulations can include more than two variables. When three or more variables are joined in a TABLES statement, the result is a series of two-way tables that are grouped by the values of the first two variables that are listed.


 * Creating Tables in list format:

To reduce the bulk of n-way table output, add a slash and the LIST option to the end of the TABLES statement. PROC FREQ then prints compact, multicolumn lists instead of a series of tables.

1.
By default, PROC FREQ creates a table of frequencies and percentages for which data set variables?

a.character variables

b.numeric variables

c.both character and numeric variables d.none:variables must always be specifies

Correct answer:c

By default, the PROC FREQ creates a table for all variables in a data set.

2.
Frequency distributions work best with variables that contain

a.continuous values

b.numeric values

c.categorical values

d.unique values

correct answer:c

Both continuous values and many unique values can result in lengthy and meaningless tables. Frequency distributors work best with categorical values.