Y8 (09/1999)

The data is grouped evenly. Class intervals chosen sensibly display the data, with not less than 3 or more than 10 in a group. The class intervals cover the range of the data, 0 to 38.

Makes one type of error.

Makes two types of errors.

Types of errors:

• The class intervals chosen may not sensibly display the data, with either too many or too few in a group. For example 5-7 is too short and 10-20 too long an interval.
• The range of the data, 0-38, is not covered.
• The groups are uneven (except the last category if it is open ended, e.g. 30+).
• The intervals overlap.

3 marks - very difficult

2 marks - difficult

1 mark - moderate