Difference between Unimodal and Bimodal Distribution


Our lives are filled with random factors that can significantly impact any given situation at any given time. The vast majority of scientific fields rely heavily on these random variables, notably in management and the social sciences, although chemistry, engineering, and physics all benefit greatly. Probabilistic and statistical qualities, including the distribution function, are analyzed and quantified. Probability distribution is what is usually meant by the word "distribution" when discussing statistical concepts.

A distribution describes a variable's range of possible values and how often they occur. A variable's modality is the value or values that constitute the majority of occurrences in a data set. The first feature of data distribution is the frequency of occurrence of the most common value(s) of the variable in question. The number of peaks in the distribution can be used to determine the modality. The frequency of the values within the distribution determines whether the distribution is unimodal or bimodal. Let's compare and contrast unimodal and bimodal distributions.

What is Unimodal Distribution?

Unimodal Distributions are those with only one "peak," meaning that one particular value occurs more frequently than the others. The fact that it is implicit in the distribution's name is evidence of this. Distributions can sometimes be perceived to have a distinct peak. Distributions are considered to be unimodal if they have just one clearly distinguishable peak or if there is only one value that is the most common. This suggests that there is a single peak in the distribution. After passing that milestone, values start to decrease after rising up to that point.

By far the most common form of unimodal distribution is the normal distribution. Sometimes the tallest point is in the center, and sometimes it's off to the right or the left. The mode is the most common value in the data. It is not possible to ensure that a unimodal distribution would be symmetric; in fact, such distributions are more likely to show asymmetry or skewness. If the distribution's mean is off-center to the left, we say it's left-skewed, and if it's off-center to the right, we say it's right-skewed.

What is Bimodal Distribution?

When there are two peaks that are nearly equal to one another, we say that the distribution exhibits bimodal features. Two values dominate the distribution, making up the vast majority of occurrences. If you look at the graph closely, you can notice that it has two humps, like a camel's back. Bi- means two, therefore bi-modal means there are two ways of doing something.

To have two peaks or two frequent values separated by a gap is indicative of a bimodal distribution. In a bimodal distribution, there are two or more distinct modes, each of which can be thought of as a particularly striking pattern within the data. The mode of a given distribution is the value that both appear most frequently and represent the peak of that distribution.

A bimodal distribution is characterized by a preponderance of two values. In most cases, there will be a considerable difference between the two modes, and this distribution has more data points than most others.

Differences: Unimodal and Bimodal Distribution

The following table highlights how a Unimodal Distribution is different from a Bimodal Distribution −

Characteristics Unimodal Distribution Bimodal Distribution

Definition

It is the frequency of the values within the distribution that determines whether the distribution is unimodal or bimodal.

Unimodality refers to a distribution in which there is one value that is more common than any others. What we have here is a distribution in which the most common occurrence, or the "peak," is a single integer.

In a bimodal distribution, the most common values are those in the middle. This suggests a discrepancy between the two most common numbers.

Importance

Distributions with a unimodal shape have a single maximum value. Sometimes the tallest point is in the center, and sometimes it's off to the right or the left.

Since it is the most often occurring number in the data, the mode is sometimes referred to as the peak.

When a distribution has two peaks that are nearly equal to one another, we say that the distribution is bimodal (or the modes).

This distribution has a greater number of observations than most others, and the distance between the two modes is wider than in most others.

Examples

One of the most prominent examples of a unimodal distribution is the Normal Distribution, which has a mean of zero and a standard deviation of one.

It has a standard deviation of 1, with a mean of 0. The chi-squared distribution, the Cauchy distribution, the exponential distribution, the Student's t-distribution, and so on are only a few examples of the numerous distributions available.

An everyday example of a bimodal distribution is the variation in traffic volume over London Bridge at different times of the day.

Between 8 a.m. and 6 p.m., there is a peak in the number of cars on the road, and the number drops off significantly. If you plot the data, you'll see that there are several peaks happening all at once.

Conclusion

In statistical terms, a unimodal distribution has a single maximum value. The term "bell-shaped profile" has been applied to it because the highest point is in the middle, and the shape of the bell slopes downward as you move away from the top, just like a bell. Many examples of unimodal distributions are given, but the Normal Distribution is by far the most common.

Conversely, a bimodal distribution is characterized by two peaks, also called two primary high points, with a valley in between that is known as the local minimum.

Updated on: 16-Dec-2022

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