Published inTowards Data Science·Jan 27Member-onlyDates and Subqueries in SQLWorking with dates in SQL — It is often the case that when working with a SQL database, one typically has to work with tables that contain a date column showing the date for each relevant record. However, the ability of SQL to work with dates and yield valuable insights from such data types is often…Sql4 min readSql4 min read
Published inTowards Data Science·Jan 25Member-onlyUsing the HAVING and DISTINCT Clauses in SQLTwo Important SQL Clauses You Should Know — SQL is a powerful tool when it comes to extracting data from a database — either from one or multiple tables. That said, there are some clauses that are particularly important when it comes to analysing data effectively. The two clauses covered in this article are the HAVING and DISTINCT…Data Science4 min readData Science4 min read
Published inTowards Data Science·Jan 13Member-onlyAnalysing NYC Yellow Taxi Trip Records with InterpretMLRegression Analysis and Counterfactual Explanations — InterpretML is an interpretable machine learning library designed by Microsoft, with the purpose of making machine learning models more understandable and open to human interpretation. This has particular value when communicating findings with business stakeholders, who in many cases are non-technical and seek to understand the business implications of findings…Machine Learning9 min readMachine Learning9 min read
Published inTowards Data Science·Nov 25, 2021Member-onlyBayesian Networks: Analysing Hotel Customer DataImplementing probabilistic modelling with bnlearn — Bayesian networks are quite an intuitive tool when it comes to examining the dependencies between different variables. Specifically, a DAG (or directed acyclic graph) is what allows us to represent the conditional probabilities between a given set of variables. Using the bnlearn library in Python, let’s take a look at…Statistics6 min readStatistics6 min read
Published inTowards Data Science·Nov 23, 2021Member-onlyAnalysing Lichess Games with RUsing ANOVA and Bootstrapping to reveal game insights — Chess has a long history, dating back some 1,500 years. However, it is only recently that the game has become a treasure trove for data analysis, thanks to the proliferation of online gaming. Players often have many questions about the extent to which one’s rating can be expected to improve…Data Science7 min readData Science7 min read
Published inTowards Data Science·Nov 21, 2021Member-onlyANOVA and the Bonferroni CorrectionGuarding against Type 1 errors — Performing a hypothesis test comes with the risk of obtaining either a Type 1 or Type 2 error. Type 1 error: Rejecting a true null hypothesis Type 2 error: Accepting a false null hypothesis When analysing different groups, a one-way ANOVA can tell us if there is a statistically significant…Data Science4 min readData Science4 min read
Published inTowards Data Science·Nov 19, 2021Member-onlyBootstrapping using Python and REstimating a sampling distribution using repeated sampling — All too often, the attempt to determine the characteristics of a population is constrained by the fact that we must rely on a sample to determine characteristics of that population. When analysing data, we would like to be able to estimate a sampling distribution in order to perform hypothesis tests…Probability5 min readProbability5 min read
Published inTowards Data Science·Nov 4, 2021Member-onlyPolymorphism in Python: Probability AnalysisObject-oriented programming using Python — Data scientists often face the accusation of writing what is known as “spaghetti code”. That is to say, code which technically accomplishes a task but is not always reproducible or laid out in the best manner. From this point of view, polymorphism — a core concept in object-oriented programming —…Data Science5 min readData Science5 min read
Published inTowards Data Science·Oct 8, 2021Member-onlyModelling Bimodal Distributions with multimode in RAnalysing distributions with more than one mode — We often think of most distributions as having one mode. This includes distributions such as the normal distribution, which is a standard reference in statistics.Statistics5 min readStatistics5 min read
Published inTowards Data Science·Oct 5, 2021Member-onlyWindow Functions in SQL: Aggregating ValuesCalculate running totals with window functions — When working with a table in SQL, it is often the case that one might wish to aggregate values, or calculate a running total among the values in the table. In this article, we will investigate how this can be done using what is called a window function. Additionally, we…Database4 min readDatabase4 min read
