SAS Chapter 9 Producing Descriptive Statistics

1. The data set Survey.Health includes the following variables. Which is a poor candidate for PROC MEANS analysis?

IDnum

Age

Height

Weight

Unlike Age, Height, or Weight, the values of IDnum are unlikely to yield any useful statistics.

Explanation

Unlike Age, Height, or Weight, the values of IDnum are unlikely to yield any useful statistics.

2. The default statistics produced by the MEANS procedure are n-count, mean, minimum, maximum, and ...

Median

Range

Standard deviation

Standard error of the mean

By default, the MEANS procedure produces the n-count, mean, minimum, maximum, and standard deviation.

Explanation

By default, the MEANS procedure produces the n-count, mean, minimum, maximum, and standard deviation.

3. Which group processing statement produced the PROC MEANS output shown below?

Class sex survive;

Class survive sex;

By sex survive;

By survive sex;

A CLASS statement produces a single large table, whereas BY group processing creates a series of small tables. The order of the variables in the CLASS statement determines their order in the output table.

Explanation

A CLASS statement produces a single large table, whereas BY group processing creates a series of small tables. The order of the variables in the CLASS statement determines their order in the output table.

4. Which PROC FREQ step produced this two-way table?

Proc freq data=clinic.diabetes; tables height weight; format height htfmt. weight wtfmt.;run;

Proc freq data-clinic.diabetes; tables weight height; format weight wtfmt. height htfmt.;run;

Proc freq data=clinic.diabetes; tables height*weight; format height htfmt. weight wtfmt.;run;

Proc freq data=clinic.diabetes; tables weight*height; format weight wtfmt. height htfmt.;run;

An asterisk is used to join the variables in a two-way TABLES statement. The first variable forms the table rows, and the second variable forms the table columns.

Explanation

An asterisk is used to join the variables in a two-way TABLES statement. The first variable forms the table rows, and the second variable forms the table columns.

5. Which statement will limit a PROC MEANS analysis to the variables Boarded, Transfer, and Deplane?

By boarded transfer deplane;

Class boarded transfer deplane;

Output boarded transfer deplane;

Var boarded transfer deplane;

To specify the variables that PROC MEANS analyzes, add a VAR statement and list the variable names.

Explanation

To specify the variables that PROC MEANS analyzes, add a VAR statement and list the variable names.

6. Which of the following statements is true regarding BY group processing?

BY variables must be either indexed or sorted.

Summary statistics are computed for BY variables.

BY group processing is preferred when you are categorizing data that contains few variables.

BY group processing overwrites your data set with newly grouped observations.

Unlike CLASS processing, BY group processing requires that your data already be indexed or sorted in the order of the BY variables. You might need to run the SORT procedure before using PROC MEANS with a BY group.

Explanation

Unlike CLASS processing, BY group processing requires that your data already be indexed or sorted in the order of the BY variables. You might need to run the SORT procedure before using PROC MEANS with a BY group.

7. Which PROC FREQ step produced this table?

Proc freq data=clinic.diabetes; tables sex weight / list; format weight wtfmt.;run;

Proc freq data=clinic.diabetes; tables sex*weight / nocol; format weight wtfmt.;run;

Proc freq data=clinic.diabetes; tables sex weight / norow nocol; format weight wtfmt.;run;

Proc freq data=clinic.diabetes; tables sex*weight / nofreq norow nocol; format weight wtfmt.;run;

An asterisk is used to join the variables in cross tabulation tables. The only results shown in this table are cell percentages. The NOFREQ option supresses cell frequences, the NOROW option suppresses row percentages, and the NOCOL option suppresses column percentages.

Explanation

An asterisk is used to join the variables in cross tabulation tables. The only results shown in this table are cell percentages. The NOFREQ option supresses cell frequences, the NOROW option suppresses row percentages, and the NOCOL option suppresses column percentages.

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

Character variables

Numeric variables

Both character and numeric variables

None: variables must always be specified

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

Explanation

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

9. Which program can be used to create the following output?

Both a and b.

You can either PROC MEANS or PROC SUMMARY to create the table. Adding a PRINT option to the PROC SUMMARY statement produces the same report as if you used PROC MEANS.

Explanation

You can either PROC MEANS or PROC SUMMARY to create the table. Adding a PRINT option to the PROC SUMMARY statement produces the same report as if you used PROC MEANS.

10. Frequency distributions work best with variables that contain

Continuous values.

Numeric values.

Categorical values.

Unique values.

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

Explanation

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