Book Image

Clojure for Data Science

By : Garner
Book Image

Clojure for Data Science

By: Garner

Overview of this book

The term “data science” has been widely used to define this new profession that is expected to interpret vast datasets and translate them to improved decision-making and performance. Clojure is a powerful language that combines the interactivity of a scripting language with the speed of a compiled language. Together with its rich ecosystem of native libraries and an extremely simple and consistent functional approach to data manipulation, which maps closely to mathematical formula, it is an ideal, practical, and flexible language to meet a data scientist’s diverse needs. Taking you on a journey from simple summary statistics to sophisticated machine learning algorithms, this book shows how the Clojure programming language can be used to derive insights from data. Data scientists often forge a novel path, and you’ll see how to make use of Clojure’s Java interoperability capabilities to access libraries such as Mahout and Mllib for which Clojure wrappers don’t yet exist. Even seasoned Clojure developers will develop a deeper appreciation for their language’s flexibility! You’ll learn how to apply statistical thinking to your own data and use Clojure to explore, analyze, and visualize it in a technically and statistically robust way. You can also use Incanter for local data processing and ClojureScript to present interactive visualisations and understand how distributed platforms such as Hadoop sand Spark’s MapReduce and GraphX’s BSP solve the challenges of data analysis at scale, and how to explain algorithms using those programming models. Above all, by following the explanations in this book, you’ll learn not just how to be effective using the current state-of-the-art methods in data science, but why such methods work so that you can continue to be productive as the field evolves into the future.
Table of Contents (12 chapters)
11
Index

Hypothesis testing


Hypothesis testing is a formal process for statisticians and data scientists. The standard approach to hypothesis testing is to define an area of research, decide which variables are necessary to measure what is being studied, and then to set out two competing hypotheses. In order to avoid only looking at the data that confirms our biases, researchers will state their hypothesis clearly ahead of time. Statistics can then be used to confirm or refute this hypothesis, based on the data.

In order to help retain our visitors, designers go to work on a variation of our home page that uses all the latest techniques to keep the attention of our audience. We'd like to be sure that our effort isn't in vain, so we will look for an increase in dwell time on the new site.

Therefore, our research question is "does the new site cause the visitor's dwell time to increase"? We decide that this should be tested with reference to the mean dwell time. Now, we need to set out our two hypotheses...