What is the meaning of a histogram with one peak?

A histogram with one peak is called unimodal, indicating that the data has a single mode or most frequent value.

In a histogram, the height of each bar represents the frequency of data points within a specific range. When a histogram has one peak, it means that there is one range where the data points are most concentrated. This peak is the mode of the dataset, which is the value or range of values that appear most frequently.

A unimodal histogram can take various shapes. If the peak is in the centre and the histogram is roughly symmetrical, it suggests a normal distribution, often referred to as a bell curve. This is common in many natural phenomena, such as heights or test scores, where most values cluster around the mean.

However, a unimodal histogram doesn't have to be symmetrical. It can be skewed to the left (negatively skewed) or to the right (positively skewed). In a left-skewed histogram, the peak is towards the right, and the tail extends to the left. Conversely, in a right-skewed histogram, the peak is towards the left, and the tail extends to the right. These shapes can indicate different characteristics of the data, such as a majority of lower or higher values.

Understanding the shape of a histogram helps in analysing the distribution and spread of the data, which is crucial for making informed decisions based on the dataset.