Answer: The correct answer is b) 7
Explanation: Class width refers to the difference between highest and lowest number divided by the number of classes.
In calculating class width, the range of the frequency distribution is first calculated before it is divided by the number of classes.
Therefore, Range = Highest number - Lowest number = 68 - 23 = 45
Class width = Range / Number of classes
= 45 / 7
= 6.428
In rounding up to the nearest whole number it becomes 7.