WorksheetsData Concepts Pre-Test
Total questions: 5
Worksheet time: 3mins
You are given a dataset where each row represents a unique customer's first purchase on an e-commerce platform. Which of the following best describes the granularity of this dataset?
Per transaction
Per product
Per unique customer's first purchase
Per daily summary
A column in your dataset contains values like "2023-04-25", "2023-05-10", and "2023-06-01". You want to calculate the number of days between purchases for each customer. What is the most appropriate data type this column should be converted to for this analysis?
String (Text)
Integer
Date/Time Object
Categorical
You've just loaded a new dataset and run a command that shows you the count of NaN values for each column. What specific aspect of data quality are you primarily assessing with this action?
Data type consistency
Data uniqueness (cardinality)
Presence and extent of missing values
Data distribution and outliers
You are analyzing a dataset of customer reviews. You notice that some reviews contain phrases like "amazing!!!" or "so bad :(." Even if the text is fully present and readable, what hidden data quality challenge might this present for sentiment analysis?
Incorrect data types
High cardinality
Ambiguity due to sarcasm or emotional nuance
Duplicate entries
What is the primary goal of performing initial data inspection steps like viewing the head()/tail() of a dataset, checking dtypes, and looking at isnull().sum()?
To immediately build predictive models
To get a quick overview of the data's structure and identify obvious issues
To perform complex statistical analysis
To generate final reports for stakeholders
