Field 2 – Date of flight start:
• Check that day, month, and year correspond to the current date.
In the data validation tool, you would select the cells you want to test and enter
the date value you want to compare to, as follows:
Field 3 – Plane used:
Field 4 – Time of take off:
Field 5 – Time of landing:
a. Suggest other controls to minimize the risk of input errors.
10.4 The first column in Table 10-3 lists transaction amounts that have been summed to
obtain a batch total. Assume that all data in the first column are correct. Cases a
through d each contain an input error in one record, along with a batch total
computed from that set of records.
For each case (a-d), compute the difference between the correct and erroneous
batch totals and explain how this difference could help identify the cause of the
error.
Solution: Differences between the correct transactions column and the batch totals
10.5 Excel Problem
Create a spreadsheet with the following columns:
• Plaintext character
• ASCII code (7-bits, binary number)
• First bit
• Second bit
• Third bit
• Fourth bit
• Fifth bit
• Sixth bit
• Seventh bit
• Number of bits with value = 1
• Parity bit for odd parity coding
• Parity bit for even parity coding
a. Enter the 26 letters a-z (lowercase) and the ten digits (0-9) in the plaintext
column
b. The ASCII column should convert the plaintext character to the binary code
used by your computer.
c. The next seven columns should each display one bit of the ASCII code,
beginning with the leftmost digit. (Hint: Excel provides text functions that can
select individual characters from a string).
d. The tenth column should sum the number of bits that have the value ‘1’. (Hint: the
text functions used to populate columns 3-9 return a text string that you will need to
convert to a numeric value).
e. The eleventh column should have a 1 if the number in the tenth column is odd and 0
if the number in the tenth column is even.
f. The twelfth column should have a 1 if the number in the tenth column is even and a
0 if the number in the tenth column is odd.
The solution should look like this:
NOTE: Tell students that one of the objectives of this exercise (besides illustrating how parity
bits work) is for them to explore the large number of built-in Excel functions. You may wish to
provide one or two examples from the solution to get them started.
Functions used to populate columns in the solution:
Column b: converting the ASCII character in column A to its binary equivalent. This is
accomplished by using the DEC2BIN and CODE functions: =DEC2BIN(CODE(A2))
• The DEC2BIN function is one of Excel’s built-in Engineering functions. It
transforms a number, in this case the result of the CODE function, into binary
(0s and 1s):
Columns C-I: the individual bits in the binary string. These are found using Excel’s Text
functions as follows:
