News / Blog: #statistics

Data Science: Which tools and methods you should know about

12/22/2023 | By: FDS

1. Python: Python is one of the most widely used programming languages for Data Science. It is a powerful open source language that can be used for many applications, including machine learning.

2. R: R is a programming language used for statistics, data mining and visualization. It is also an open source language that is easy to learn and has many applications for Data Science.

3. SQL: SQL is a standard programming language used for querying and manipulating databases. It is an essential tool for Data Scientists as it provides a way to store and retrieve data.

4. Machine learning frameworks: machine learning frameworks such as TensorFlow, PyTorch, and Scikit-Learn provide developers with extensive machine learning libraries. These frameworks can be used to create algorithms that learn on data to perform specific tasks.

5. Data Visualization Tools: Data Visualization Tools such as Tableau, Matplotlib, and Seaborn help Data Scientists present data in an appealing and informative way. With the right tools, data can be easily interpreted to discover trends and other important insights.

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What is the difference between descriptive and inferential statistics?

10/13/2023 | By: FDS

Descriptive statistics and inferential statistics are two main branches of statistical analysis that focus on different aspects.

Descriptive statistics is concerned with describing and summarizing data. It includes the presentation and interpretation of data using metrics, graphs, and summaries in tabular form. Your goal is to identify patterns, trends, and characteristics of the data at hand. Descriptive statistics answer questions like "What happened?" or "What does the data look like?"

Inferential statistics, on the other hand, is concerned with making inferences about a population based on sample data. It enables statements to be made about the underlying population based on the available data. Inferential statistics uses methods such as hypothesis testing, confidence intervals, and estimation to make statistical inferences. Their goal is to go beyond the available data and make more general statements. Inferential statistics answer questions like "Is the observed difference between the groups statistically significant?" or "How well does the sample represent the population?"

In summary, descriptive statistics describe data and provide summaries, while inferential statistics draw conclusions about a population based on sample data. Both branches complement each other and are important for understanding and analyzing data.

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What is the concept of robustness in statistics and how is it evaluated?

10/10/2023 | By: FDS

In statistics, the concept of robustness refers to the ability of a statistical method to provide stable and reliable results even when the underlying assumptions are violated or the data contain outliers. Robust methods are less prone to extreme values ​​or violations of the assumptions and provide robust estimates or test results.

The robustness of a statistical method is usually assessed by comparison with other methods or by simulation experiments. There are several criteria that are taken into account when assessing robustness:

Influence analysis: The method is checked for how strongly individual observations or outliers influence the results. A robust method should be relatively insensitive to single observations that deviate greatly from the rest of the sample.

Comparison with non-robust methods: The robust method is compared with non-robust methods to show that it gives better or comparable results in violation of the assumptions or in the presence of outliers.

Simulation studies: The robustness of a method can be evaluated by simulating data with known properties, such as outliers or violations of assumptions. The results of the method are compared to the true values ​​or the results of other methods to assess their performance.

Theoretical Analysis: In some cases, mathematical or theoretical analysis can be used to assess the robustness of a method. This often involves examining the impact of data breaches on the properties of the method.

It is important to note that robustness is not an absolute property. One method may be more robust than others, but still potentially vulnerable to certain types of breaches or runaways. Therefore, it is advisable to consider different aspects of robustness in order to select the appropriate method for a particular statistical analysis.

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What are robust statistics and how do they differ from non-robust statistics?

09/29/2023 | By: FDS

Robust statistics are methods of data analysis that are resilient to outliers and bias in the data. In contrast, non-robust statistics are prone to outliers and can be heavily influenced by deviating values.

When there are outliers in a data set, they are values ​​that differ significantly from the other data points. These outliers can be caused by various factors, such as measurement errors, unusual conditions, or real but rare events.

Non-robust statistics often use assumptions about the distribution of the data, such as the normal distribution. If these assumptions are violated, outliers can lead to unreliable results. For example, the mean and standard deviation can be greatly affected when outliers are present.

Robust statistics, on the other hand, try to minimize the impact of outliers. They are based on methods that are less sensitive to deviating values. An example of a robust statistic is the median, which represents the middle value in a sorted series of data. The median is less prone to outliers because it's not based on the exact location of the values, just their relative rank.

Another example of a robust statistic is the MAD (Median Absolute Deviation), which measures the dispersion of the data around the median. The MAD uses the median instead of the standard deviation to provide more robust estimates of spread.

In general, robust statistics have the advantage of providing more reliable results when there are outliers or biases in the data. They are less prone to violating assumptions about the distribution of the data and can be a better choice in many situations, especially when the data is incomplete, inaccurate, or non-normal.

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How to determine the sample size in statistics?

09/28/2023 | By: FDS

Determining sample size in statistics depends on several factors, such as the desired confidence level, the expected standard deviation, the expected effect, and the desired precision of the estimate. There are several approaches to determining sample size, some of which I would like to introduce:

Confidence Level and Error Tolerance: determine the desired confidence level (usually 95% or 99%) and the maximum tolerance or precision you can accept for your estimate. These factors determine the width of the confidence interval around your estimate.

Standard deviation: estimate the standard deviation of the population or use estimates from previous studies. The standard deviation is a measure of the spread of the data around the mean.

Effect size: If you want to examine a specific effect size or difference between groups, you should use an estimate of the expected effect. For example, this could be the expected difference between the means of two groups.

Select the appropriate statistical test:Depending on the type of test (e.g., t-test, chi-square test) and the parameters you choose, use an appropriate formula to determine the sample size. These formulas are based on statistical assumptions and are specific to each test.

Determining sample size in statistics depends on several factors, such as the desired confidence level, expected standard deviation, expected effect, and desired

Use sample size calculation software: There are several online tools and software packages that can help you calculate sample size. These tools take into account the factors mentioned above and provide you with an estimate of the required sample size.

It is important to note that determining the sample size involves some uncertainty, as it is based on estimates and assumptions. It is often advisable to select a larger sample to ensure that the results are reliable and representative.

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