Business Intelligence Quiz: Reading SAS Data Sets Overview

1. If you submit the following program, which variables appear in the new data set? data work.cardiac(drop=age group); set clinic.fitness(keep=age weight group); if group=2 and age>40; run;

None

Weight

Age, Group

Age, Weight, Group

The variables Age, Weight, and Group are specified using the KEEP= option in the SET statement. After processing, Age and Group are dropped in the DATA statement.

Explanation

The variables Age, Weight, and Group are specified using the KEEP= option in the SET statement. After processing, Age and Group are dropped in the DATA statement.

2. Which of the following programs correctly reads the data set Orders and creates the data set FastOrdr?

Data catalog.fastordr(drop=ordrtime); set july.orders(keep=product units price); if ordrtime<4; Total=units*price;run;

Data catalog.orders(drop=ordrtime); set july.fastordr(keep=product units price); if ordrtime<4; Total=units*price;run;

None of the above

You specify the data set to be created in the DATA statement. The DROP= data set option prevents variables from being written to the data set. Because you use the variable OrdrTime when processing, you cannot drop OrdrTime in the SET statement. If you use the KEEP= option in the SET statement, then you must list OrdrTime as one of the variables to be kept.

Explanation

You specify the data set to be created in the DATA statement. The DROP= data set option prevents variables from being written to the data set. Because you use the variable OrdrTime when processing, you cannot drop OrdrTime in the SET statement. If you use the KEEP= option in the SET statement, then you must list OrdrTime as one of the variables to be kept.

3. The DATA step executes:

Continuously if you use the POINT= option and the STOP statement.

Once for each variable in the output data set.

Once for each observation in the input data set.

Until it encounters and OUTPUT statement.

The DATA step executes once for each observation in the input data set. You use the POINT= option with the STOP statement to prevent continuous looping.

Explanation

The DATA step executes once for each observation in the input data set. You use the POINT= option with the STOP statement to prevent continuous looping.

4. Assuming that the data set Company.USA has five or more observations, what is the result of submitting the following program? data work.getobs5(drop=obsnum); obsnum=5; set company.usa(keep=manager payroll) point=obsnum; output; stop; run;

An error

An empty data set

A continuous loop

A data set that contains one observation

By combining the POINT= option with the OUTPUT and STOP statements, your program can write a single observation to output.

Explanation

By combining the POINT= option with the OUTPUT and STOP statements, your program can write a single observation to output.

5. What is the result of submitting the following program? data work.addtoend; set clinic.stress2 end=last; if last; run;

An error

An empty data set

A continuous loop

A data set that contains one observation

This program uses the END= option to name a temporary variable that contains an end-of-file marker. That variable _last_ is set to 1 when the set statement reads the last observation of the data set.

Explanation

This program uses the END= option to name a temporary variable that contains an end-of-file marker. That variable _last_ is set to 1 when the set statement reads the last observation of the data set.

6. Which of the following Statements is false about BY-group processing? When you use the BY statement with the SET statement:

The data sets listed in the SET statement must be indexed or sorted by the values of the BY variable(s).

The DATA step automatically creates two variables, FIRST., and LAST., for each variable in the BY statement.

FIRST. and LAST. identify the first and last observation in each BY group, respectively.

FIRST. and LAST. are stored in the data set.

When you use the BY statement with the SET statement, the DATA step creates the temporary variables FIRST. and LAST. They are not stored in the data set.

Explanation

When you use the BY statement with the SET statement, the DATA step creates the temporary variables FIRST. and LAST. They are not stored in the data set.

7. There are 500 observations in the data set Usa. What is the result of submitting the following program? data work.getobs5(drop=obsnum); obsnum=5; set company.usa(keep=manager payroll) point=obsnum; stop; run;

An error

An empty data set

Continuous loop

A data set that contains one observation

The DATA step writes observations to output at the end of the DATA step. However, in this program, the STOP statement stops processing before the end of the DATA step. An explicit OUTPUT statement is needed in order to produce observations.

Explanation

The DATA step writes observations to output at the end of the DATA step. However, in this program, the STOP statement stops processing before the end of the DATA step. An explicit OUTPUT statement is needed in order to produce observations.

8. Which of the statements is true regarding direct access of data sets?

You cannot specify END= with POINT=.

You cannot specify OUTPUT with POINT=.

You cannot specify STOP with END=.

You cannot specify FIRST. with LAST.

The END= option and POINT= option are incompatible in the same SET statement. Use one or the other in your program.

Explanation

The END= option and POINT= option are incompatible in the same SET statement. Use one or the other in your program.

9. At the start of DATA step processing, during the compilation phase, variables are created in the program data vector (PDV), and observations are set to:

Blank

Missing

0

There are not observations

At the bottom of the DATA step, the compilation phase is complete and the descriptor portion of the new SAS data set is created. There are no observations because the DATA step has not yet executed.

Explanation

At the bottom of the DATA step, the compilation phase is complete and the descriptor portion of the new SAS data set is created. There are no observations because the DATA step has not yet executed.

10. There is no end-of-file condition when you use direct access to read data, so how can your program prevent a continuous loop?

Do not use a POINT= variable.

Check for an invalid value of the POINT= variable.

Do not use an END= variable.

Include an OUTPUT statement.

To avoid a continuous loop when using direct access, either include a STOP statement or use programming logic that checks for an invalid value of the POINT= variable. If SAS reads an invalid value of the POINT= variable, it sets the automatic variable _ERROR_ to 1. You can use this information to check for conditions that cause continuous processing.

Explanation

To avoid a continuous loop when using direct access, either include a STOP statement or use programming logic that checks for an invalid value of the POINT= variable. If SAS reads an invalid value of the POINT= variable, it sets the automatic variable _ERROR_ to 1. You can use this information to check for conditions that cause continuous processing.