Step 1 :First, we need to find the range of the data, which is the difference between the maximum and minimum values.
Step 2 :The maximum value in the data is 21 and the minimum value is 3.
Step 3 :So, the range is \(21 - 3 = 18\).
Step 4 :Next, we need to divide the range by the number of classes. In this case, we have 4 classes.
Step 5 :So, the class width is \(18 / 4 = 4.5\). However, we usually round up to the nearest whole number for ease of interpretation, so we'll use a class width of 5.
Step 6 :Now, we can construct the frequency table. The first class will be 3-7 (including 3 and excluding 8), the second class will be 8-12, the third class will be 13-17, and the fourth class will be 18-22.
Step 7 :We then count the number of data points in each class. For example, the number of data points in the first class (3-7) is 5.
Step 8 :We repeat this process for the other classes.
Step 9 :Finally, we write down the frequency table as follows:
Step 10 :\begin{tabular}{|c|c|}\hline Hours & Number of Employees \\hline $3.0-7.9$ & 5 \\hline $8.0-12.9$ & 6 \\hline $13.0-17.9$ & 5 \\hline $18.0-22.9$ & 4 \\hline\end{tabular}
Step 11 :Final Answer: The frequency table is shown above with a class width of \(\boxed{5}\).