WAEC SSCE - Computer Studies - 2021 (Essay)

Answer Details

(a) What are "Reports" in a database system?

A report is a database object used to organise, summarise and present data from one or more tables or queries in a formatted, printable layout. Reports are designed mainly for output: they allow the user to arrange records neatly, group and sort them, perform calculations such as totals and averages, and produce professional printed documents such as invoices, result sheets or mailing lists.

(b) Four ways in which reports can be viewed in a database management system (MS Access):

1. Report View - shows the finished report on screen as a continuous view.
2. Print Preview - shows exactly how the report will look when printed, page by page.
3. Layout View - shows the report with live data while allowing you to adjust the design and column widths.
4. Design View - shows the underlying structure (sections such as header, detail and footer) for detailed editing of the report.

(c) Steps to print a report in MS Access:

1. Open the database and, in the Navigation Pane, locate and open (or select) the report you want to print.
2. Switch to Print Preview to confirm the layout, page size and orientation are correct.
3. Click the File tab (or the Office/Backstage button) and choose Print.
4. In the Print dialog box, select the correct printer and set the options (number of copies, page range).
5. Click OK (or Print) to send the report to the printer, then collect the printout.

Answer Details

(a) Convert \(AB1_{16}\) to the Octal system

Step 1: Write each hexadecimal digit as 4 binary bits.

\[A=1010,\quad B=1011,\quad 1=0001\]

\[AB1_{16}=1010\,1011\,0001_2\]

Step 2: Regroup the binary digits in threes from the right.

\[101\;010\;110\;001\]

Step 3: Convert each group of three to its octal digit.

\[101=5,\;010=2,\;110=6,\;001=1\]

\[\therefore AB1_{16}=5261_8\]

(b) Convert \(1110111.101_2\) to the Denary (base 10) system

Integer part, using place values \(64,32,16,8,4,2,1\):

\[1110111_2=64+32+16+0+4+2+1=119\]

Fractional part, using place values \(\tfrac{1}{2},\tfrac{1}{4},\tfrac{1}{8}\):

\[.101_2=1(0.5)+0(0.25)+1(0.125)=0.625\]

\[\therefore 1110111.101_2=119.625_{10}\]

(c) Convert \(507_8\) to the Binary system

Since the digit 7 is not valid in base 2, the number is in the octal system. Write each octal digit as 3 binary bits.

\[5=101,\quad 0=000,\quad 7=111\]

\[\therefore 507_8=101\,000\,111_2=101000111_2\]

Check by way of denary: \(507_8=5\times8^2+0\times8^1+7\times8^0=320+0+7=327_{10}\), and repeated division of \(327\) by 2 gives \(101000111_2\), confirming the result.

Answer Details

QBASIC program to grade a score as "Poor" or "Satisfactory"

The program keeps asking for a score. If the score entered is less than zero, it stops immediately. Otherwise it prints "Poor" for a score below 50 and "Satisfactory" for a score of 50 or above.

REM Program to grade scores
CLS
DO
    INPUT "Enter a score (negative to stop): ", SCORE
    IF SCORE < 0 THEN
        EXIT DO
    END IF
    IF SCORE < 50 THEN
        PRINT "Poor"
    ELSE
        PRINT "Satisfactory"
    END IF
LOOP
END

How it works:

• The DO ... LOOP repeats so that many scores can be graded one after another.
• INPUT reads a score from the keyboard.
• If SCORE < 0, the EXIT DO statement ends the loop and the program stops.
• The IF ... ELSE statement tests the score: below 50 prints Poor; equal to or above 50 prints Satisfactory (since 50% is the boundary and belongs to Satisfactory).

Alternative using GOTO (also acceptable):

CLS
Start:
INPUT "Enter a score: ", SCORE
IF SCORE < 0 THEN END
IF SCORE < 50 THEN PRINT "Poor" ELSE PRINT "Satisfactory"
GOTO Start