Computer Science: Data Science Fundamentals

What is a pandas DataFrame?

A two-dimensional, size-mutable, and potentially heterogeneous tabular data structure with labeled axes (rows and columns).

Which pandas function is used to load data from a comma-separated values file into a DataFrame?

pd.read_csv()

What is the primary data structure in NumPy used for numerical computing?

The ndarray (n-dimensional array).

In a standard box plot, what does the box itself represent?

The Interquartile Range (IQR), which spans from the first quartile (Q1) to the third quartile (Q3), containing the middle 50% of the data.

What is the primary goal of the 'Data Cleaning' stage in the data science pipeline?

To identify and correct errors, handle missing values, and remove inconsistencies to ensure the data is accurate and high-quality for analysis.

Which Python library is built on top of Matplotlib and provides a high-level interface for drawing attractive statistical graphics?

Seaborn

Explain the concept of 'Broadcasting' in NumPy.

Broadcasting is a mechanism that allows NumPy to perform arithmetic operations on arrays of different shapes by 'stretching' the smaller array to match the dimensions of the larger one.

Describe the three steps of the 'Split-Apply-Combine' strategy used in pandas groupby operations.

1. Split: Data is divided into groups based on a key. 2. Apply: A function (like mean or sum) is calculated for each group. 3. Combine: Results are merged into a new data structure.

What is the difference between an 'inner join' and an 'outer join' when using pd.merge()?

An inner join returns only rows with matching keys in both DataFrames, while an outer join returns all rows from both, filling missing matches with NaN.

What is the formula for Min-Max Normalization to scale a feature x to the range [0, 1]?

x_scaled = (x - x_min) / (x_max - x_min)