Statistics
Histograms

Statistics

• Discrete vs continuous data
• Mean, median and mode
• ​Estimating the mean of grouped data
• ​Range & Interquartile Range (IQR)
• ​Box plots
• Frequency tables
• Histograms
• Stem-and-leaf plots
• ​Back-to-back stem-and-leaf plots
• Describing distribution of data​

When data is recorded for a continuous numerical variable, there will be many different values. Therefore the data is grouped into class intervals with lower and upper bounds which can be displayed in a frequency table or a histogram.
A frequency histogram is similar to a column graph, but to account for the continuous nature of the variable, there are no gaps between the columns.