FREE Data Science Analysis Question and Answers

Question 1

On a bank's website, information has been gathered about visitors' viewing patterns. Which method is employed to determine which pages are frequently viewed simultaneously on the website?

Accepted Answer

Association Rules

Answer

Association rules are a data mining technique used to discover relationships between variables in large datasets, often expressed as 'if-then' statements. In the context of a bank's website, they can identify which pages are frequently viewed together in user sessions. This method helps uncover patterns of co-occurrence, useful for understanding user behavior and making recommendations.

Question 2

The task of creating a model from a reporting data warehouse is given to a data scientist. The warehouse houses data that has been processed through a difficult, multi-stage ETL process using data gathered from numerous sources. What should the data scientist be worried about in terms of the data?

Accepted Answer

It is too processed

Answer

Data in a reporting data warehouse, especially after a complex multi-stage ETL process, is often highly aggregated, transformed, and summarized for specific reporting needs. While beneficial for reporting, this extensive processing can remove granular details, introduce biases, or obscure relationships crucial for building robust predictive models. Data scientists often prefer less processed data to ensure model accuracy and flexibility.

Question 3

When would a Wilcoxson Rank Sum test be appropriate?

Accepted Answer

When you cannot make an assumption about the distribution of the populations

Answer

The Wilcoxon Rank Sum test, also known as the Mann-Whitney U test, is a non-parametric statistical test. It is appropriate when comparing two independent groups and you cannot make assumptions about the underlying distribution of the populations, such as normality. This test ranks the data and compares the sums of the ranks between the groups.

Question 4

What data science requirement is the most fundamental?

Accepted Answer

Collect

Answer

Data collection is the most fundamental requirement in data science. Without data, there is nothing to analyze, transform, model, or learn from. All subsequent steps in the data science pipeline, such as exploration, cleaning, storage, and model building, are entirely dependent on having relevant and accessible data.

Question 5

What role does the Reduce function play in the MapReduce framework?

Accepted Answer

It distributes the input to multiple nodes for processing.

Answer

In the MapReduce framework, the Reduce function processes the intermediate key-value pairs generated by the Map tasks. Before reaching the Reduce function, these intermediate results are shuffled and sorted, effectively distributing them to the appropriate reducer tasks across multiple nodes. Thus, the Reduce function is a crucial component in the overall distributed processing pipeline, working on data that has been distributed for aggregation.

Data Science Practice Test

Data Science Practice Test

FREE Data Science Analysis Question and Answers