Holistic Health. Weight gain that occurs when your weight increases without increasing your food intake has many causes. Thyroid hormone deficiency may slow metabolism, resulting in weight gain from fat gain and water retention.
used when the range is large and classes several units in width are needed ungrouped frequency distribution used for numerical data and when range of data is small; each class is only one unit
All the method are to be used for suitable type of data. Cluster sampling is one of the important methods of sampling. Sometimes, there is a very-very big and almost impossible field of study is available. Cluster sampling makes data manageable for research and further processing.