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Given in the question that the additional sleep, to the nearest tenth of an hour, was obtained by a sample of 100 patients by using a particular brand of sleeping pill.

Single-value grouping:

To gather statistical analysis, employ classes in which each class represents a single possible value; these classes are known as single-value classes, and single-value grouping is the way of grouping quantitative data.

Limit grouping:

To group quantitative data, class limits are used. Each class is made up of a number of different values. The lower limit of the class is the smallest value that can be entered, and the upper limit of the class is the highest value that may be entered. Limit grouping is a method of categorising quantitative data.

Cut-point grouping:

To group quantitative data, class cut-points are used, with each class containing a set of values. The lower cut-points of a class are the smallest values that could fit in it, while the upper cut-points are the smallest values that could fit in the next higher class.

Cut-point grouping is a technique for dividing quantitative data into groups using cut-points.

Think about it.

The extra sleep gained by a group of 100 patients using a specific type of sleeping drug, was measured to the closest tenth of an hour.

The extra sleeping times are taken into account for $100$patients, resulting in decimal figures, which are rounded to the nearest hour.

Sleeping schedules are not in entire numbers. As a result, single value grouping is not an option.