SAS Chapter 16 Processing Variables With Arrays

1. For the program below, select an iterative DO statement to process all elements in the contrib array. data work.contrib array contrib{4} qtr1-qtr4; ... contrib{i}=contrib{i}*1.25; end; run;

Do i=4;

Do i=1 to 4;

Do until i=4;

Do while i le 4;

In the DO statement, you specify the index variable that represents the values of the array elements. Then specify the start and stop positions of the array elements.

Explanation

In the DO statement, you specify the index variable that represents the values of the array elements. Then specify the start and stop positions of the array elements.

2. What belongs within the braces of this ARRAY statement? array contrib{?} qtr1-qtr4;

Quarter

Quarter*

1-4

4

The value in parentheses indicates the number of elements in the array. In the case, there are four elements.

Explanation

The value in parentheses indicates the number of elements in the array. In the case, there are four elements.

3. What is the value of the index variable that references Jul in the statements below? array quarters{4} Jan Apr Jul Oct; do i=1 to 4; yeargoal=quarter{1}*1.2; end;

1

2

3

4

The index value represents the positions of the array element. In this case, the third element is Jul.

Explanation

The index value represents the positions of the array element. In this case, the third element is Jul.

4. Finish the ARRAY statement below to create temporary array elements that have initial values of 9000, 9300, 9600, and 9900. array goal{4} ... ;

_temporary_ (9000 9300 9600 9900)

Temporary (9000 9300 9600 9900)

_temporary_ 9000 9300 9600 9900

(temporary) 9000 9300 9600 9900

To create temporary array elements, specify _TEMPORARY_ after the array name and dimension. Specify an initial value for each element, separated by either blanks or commas, and enclose the values in parentheses.

Explanation

To create temporary array elements, specify _TEMPORARY_ after the array name and dimension. Specify an initial value for each element, separated by either blanks or commas, and enclose the values in parentheses.

5. Select the ARRAY statement that defines the array in the following program. data rainwear.coat; input category high1-high3 / low1-low3; ... do i=1 to 2; do j=1 to 3; compare{i,j}=round(compare{i,j}*1.12); end; end; run;

Array compare{1,6} high1-high3 low1-low3;

Array compare{2,3} high1-high3 low1-low3;

Array compare{3,2} high1-high3 low1-low3;

Array compare{3,3} high1-high3 low1-low3;

The nested DO loops indicate that the array is named compare and is a two-dimensional array that has two rows and three columns.

Explanation

The nested DO loops indicate that the array is named compare and is a two-dimensional array that has two rows and three columns.

6. Which statement is false regarding an ARRAY statement?

It is an executable statement

It can be used to create variables

It must contain either all numeric or all character elements

It must be used to define an array before the array name can be referenced.

An array statement is not an executable statement; it merely defines an array.

Explanation

An array statement is not an executable statement; it merely defines an array.

7. Which statement below is false regarding the use of arrays to create variables?

The variables are added to the program data vector during the compilation of the DATA step.

You do not need to specify the array elements in the ARRAY statement.

By default, all character variables are assigned a length of eight.

Only character variables can be created.

Either numeric or character variables can be created by an ARRAY statement.

Explanation

Either numeric or character variables can be created by an ARRAY statement.

8. For the first observation, what is the value of diff{i} at the end of the second iteration of the DO loop?

15

10

8

-7

At the end of the second iteration, diff{i} resolves as follows:
diff{2}=wt{2+2};
diff{2}=215-200

Explanation

At the end of the second iteration, diff{i} resolves as follows:
diff{2}=wt{2+2};
diff{2}=215-200

9. Which DO statement would not process all the elements in the factors array shown below? array factors{*} age height weight bloodpr;

Do i=1 to dim (factors);

Do i=1 to dim(*)

Do i=1,2,3,4;

Do i=1 to 4;

To process all the elements in an array, you can either specify the array dimension or use the DIM function with the array name as the argument.

Explanation

To process all the elements in an array, you can either specify the array dimension or use the DIM function with the array name as the argument.

10. Based on the ARRAY statement below, select the array reference for the array element q50. array ques{3,25} q1-q75;

Ques{q50}

Ques{1,50}

Ques{2,25}

Ques{3,0}

This two-dimensional array would consist of three rows of 25 elements. The first row would contain q1 through q25, the second row would start with q26 and end with q50, and the third row would start with q51 and end with q75.

Explanation

This two-dimensional array would consist of three rows of 25 elements. The first row would contain q1 through q25, the second row would start with q26 and end with q50, and the third row would start with q51 and end with q75.