Statistics is taught in schools as part of mathematics, but it is treated as a separate subject at the advanced level. Statistics is important, and many students choose to pursue a career in it. It’s used in practically every industry, including banking, finance, medicine, and weather forecasting. However, several students believe it is a difficult subject. Several subjects and phrases in statistics are difficult to comprehend. We will cover types of distribution in statistics, which is one of the statistical topics.
In statistics, a distribution is a parametrized mathematical function. In statistics, there are various types of distribution, and each book lists them along with their attributes. This blog will provide you with all of the necessary knowledge on different types of statistical distributions, including examples. But first, let’s define statistical distribution.
What is statistical distribution?
In statistics, a distribution is a function that describes all of the potential values for a variable and how often they occur.
Let’s use a dice as an example. It includes six numbered surfaces ranging from 1 to 6. We take a chance. What are the chances of getting 1?
Isn’t it one out of six, or one-sixth? So, what are the chances of getting two? One-sixth, once more. Okay!
The same is true for 3, 4, 5, and 6.
So, what are the chances of getting a 7? Obviously, rolling a dice and getting a 7 is impossible.
As a result, the likelihood is zero.
Note that the probability of universal truth is 1 and the probability of assumptions is 0.
Examples of several types of statistical distributions
Standard Deviation
The bell curve is another name for the normal distribution. It happens naturally in a variety of situations; for example, the normal distribution can be seen in GRE and SAT assessments. There are also a number of groupings that follow the normal distribution pattern. As a result, it is commonly employed in statistics, industry, and government agencies such as the FDA:
- Errors in measurement
- A test’s points.
- Salaries.
- People’s height.
- High blood pressure
- IQ tests.
A normal distribution’s characteristics
- The curve is symmetrical in the middle.
- The radius of the curve is one.
- The average, median, and mode are all the same.
- Half of the value is on the left, while the other is on the right.
As an example
Height
Population Normal distribution can be shown in height. A number of persons in the population are of ordinary height, while some are taller or shorter than average. As a result, height is not a single trait. Height is influenced by both hereditary and environmental factors. As a result, it resembles the normal distribution.
Distribution T
It is one of the most significant statistical distributions. Student’s t-distribution is another name for the probability distribution. When the sample size is small, this method is used to estimate the population’s parameters. And the population’s standard deviation is unknown.
T-distribution properties
- The student distribution is bell-shaped and symmetric with zero mean, just like the normal distribution.
- The student distribution ranges from – to (infinity).
- The shape of the t distribution changes as the degree of freedom increases.
- The variance is always more than one, and it may be expressed as Var (t) = [v/v -2] for the degree of freedom V>=3.
- It is not as densely packed in the center as it is at the extremities, giving it a platykurtic shape.
- The t distribution has substantially higher dispersion than the normal distribution. A normal distribution is examined as the size of the sample ‘n’ grows larger. The sample size is greater than n>=30 in this case.
As an example
Assume a researcher wants to test the hypothesis of a sample of 25 people with a mean of 79.
population with mean = 75 and standard deviation s = 10
Using the t-distribution formula, t = x – / s / n
t will be computed to be 2.
a consistent distribution
The uniform distribution is the most fundamental type of continuous distribution. It has a constant chance of forming a rectangular distribution. It also means that each value has the same distribution length. Which has an equal chance of happening. This function, on the other hand, belongs to the category of maximum entropy probability distributions.
Uniform distribution characteristics
- The density function adds up to one.
- Its input functions are all equally weighted.
- The mean of the uniform function is:
- The uniform distribution’s variance is provided by:
Bernoulli probability distribution
A Bernoulli distribution is a discrete probability distribution that represents a random trial with two outcomes. A single coin toss is an example of a special case with the value n = 1.
Bernoulli distribution characteristics
- The number of trials that must be completed as part of a single experiment must be predetermined.
- Every trial must have two possible outcomes: success or failure.
- Each experiment’s success probability should be the same.
- The trials should be independent of one another, meaning that the outcome of one trial is unaffected by the outcome of the other.
Properties
E(x) = p gives the expected value of the randomly selected variable, which can be calculated as follows:
E(x) = 0*(1-p) + 1 * p = p E(x) = 0*(1-p) + 1 *
The Bernoulli variable’s variance is given by p*(1-p) and is written as:
p2 = p* Var(X) = p – p2 (1-p)
As an example
Coins. Bernoulli’s distribution is best and simplest explained using a coin. Assume that the outcome of tails is a win and the outcome of heads is a loss. The probability of successful outcomes is expressed as p in this example, while the chance of failed outcomes is written as q, which is calculated as 1 – **p.
As a result, we know that the odds of falling on tails or heads are 50/50. As a result, in this case: **0.5 p = 0.5q = 1
In this case, however, both p and q are equal to 0.5.
Also See
- A Comprehensive Guide to Statistics in Mathematics
- How to Use SPSS for Descriptive Statistics
- Misuse of Statistics- What Causes Statistics Misuse?
Binomial probability distribution
Under a set of assumptions or parameters, a probability distribution concludes the value that takes one of two independent values. Furthermore, the assumptions of the binomial distribution must yield a single result with the same likelihood of success. And each trail must be distinct from the others.
Binomial distribution properties
- Each of the independent trails in an experiment has two outcomes: success or failure.
- The bi-parametric distribution is another name for the binomial distribution. It is categorised using the n and p parameters.
- This has a mean value of = np.
- The variance of a binomial distribution is given by: 2 = npq
- The value of p and q must always be less than or equal to 1, or the variance must be smaller than the mean value: npq np np np
As an example
Medical professionals use binomial distribution to determine the side effects of medications. This allows them to determine the number of patients that have side effects from new drugs.
Poisson probability distribution
When you know the value of an event, you can use it to predict a particular probability of that event. The Poisson distribution tells us how likely a given number of events will occur in a given amount of time.
Poisson distribution properties
- The random variable’s expected value and variance are the same thing.
- The absolute deviation linked with the mean is calculated as follows:
- The index dispersion is, whereas the coefficient of variance is.
- The Poisson distribution’s anticipated value is decomposed by underlying the product of intensity and exposure.
- “m” represents the Poisson distribution’s mean.
As an example The Poisson Distribution is used by call centers to represent the estimated number of calls per hour. As a result, they have a general idea of how many call center agents they’ll need.
Exponential probability distribution
The time between the trails in a Poisson process is represented by a negative exponential distribution. The exponential distribution and the Poisson distribution have a link.
Some of the formulas are as follows:
- The anticipated value of an exponential random variable is given by:
- The variance of an exponential random variable is given by:
- The moment generating function of an exponential random variable is:
- The characteristic function of an exponential random variable is:
As an example
The time between two earthquakes is represented by an exponential distribution.
Distribution in beta
It’s a group of continuous probability distributions that fall within the [0,1] interval and are represented by alpha and beta. Furthermore, this approach is applied to the scenario of a random experiment with an undetermined success probability. It also includes a strong tool that uses basic statistics to calculate the completion time confidence level.
Beta distribution properties
These distributions can be satisfied by a number of properties:
The following are the phrases used to describe the core tendency:
- Mean
- Mean Harmonic
- Mode
- Median
- Mean Geometric
The following words are used to describe statistical dispersion:
- Covariance and geometric variance
- Variance
- Absolute mean departure from the mean
- Absolute mean difference
As an example
The proportion of broken items in a shipment is one of the events that Beta Distribution may model.
The time it took to finish a task.
Beta-binomial probability distribution
It’s the most basic Bayesian model, and it’s utilized in intelligence testing, epidemiology, and marketing. If the probability of success is p and the form of the beat binomial parameter is > 0 and > 0, the distribution is said to be beta-binomial.
The success probability can be defined as the parametric shape:
- For bigger values of and, a distribution can resemble a binomial distribution.
- If the value of both and is equal to 1, the discrete uniform distribution equals the distribution from 0 to n.
- The beta-binomial distribution has the same value as the Bernoulli distribution when n = 1.
The main difference between a beta-distribution and a binomial distribution is that in a binomial distribution, p is always fixed for a set of trials, whereas in a beta-binomial distribution, p is not constant and changes from trial to trial.
Log-normal probability distribution
The variable is considered lognormally distributed if the log to the power is normally distributed. Alternatively, we can argue that ln(x) is normally distributed and that x has a log-normal distribution.
The log-normal distribution’s properties
- The anticipated value, often known as the mean of a distribution, provides information about what an average person would expect from a series of trial numbers.
- Another aspect of central tendency is the median of a log-normal distribution, which is important for outliers that help the means to lead.
- The mode of a distribution is the value that has the greatest chance of occuring.
- The variance can be used to determine how information is spread out. Because the square root of the variance and the standard deviation share the same data unit, they are useful.
For a continuous probability distribution, these values are significantly easier to calculate. However, because the measure incorporates some calculus, the description can be brief.
As an example
The examples that can be modeled with a log-normal distribution are as follows:
Milk Production by Cows
The size distribution of raindrops
The amount of gas in a petroleum reserve, for example.
Conclusion
This blog has described the various types of statistical distributions, with examples and attributes. Furthermore, this can assist pupils in comprehending the complex jargon of statistics. As a result, you must attentively study this blog in order to comprehend each term. Statistics distribution is also required for writing an assignment during their academic education.
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Question Frequently Asked
What does normal distribution have another name?
The Gaussian distribution is another term for the normal distribution.
What types of distribution channels are there?
Three types of distribution channels exist. They exist;
Wholesalers
Retailers
Consumer direct sales
