Question

How many classes are recommended in a histogram of a data set with more than 50 observations?

Answer 1

Actually there is no any proper rule or scientific rule for deciding the exact number of classes for the histograms of data sets with more than 50 observations. But, there is a general thumb rule for deciding the number of classes. If your data set consists of 25 to 30 observations, then we use 4 to 6 classes. If your data set consists of 3 to 50 observations, then we use 7 to 14 classes. If data set consists of more than 50 observations, then we can use 15 or more classes.

Remember, sometimes manual judgment is required for preparing data for histograms and different software’s use different techniques for creating histograms.