Practice Test GeeksDA - Data Analyst Practice Test
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Data Analysis Tools and Programming Flashcards

6 cards from real DA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. What does the pandas .fillna() method do?

    Answer: Fills missing NaN values with a specified value or method

    fillna() replaces NaN values in a DataFrame with a specified scalar, dictionary, or forward/backward fill method.

  2. What is the purpose of Excel's IF function?

    Answer: Returns one value if a condition is true and another if it is false

    The IF function tests a logical condition and returns the 'true value' if met or the 'false value' if not.

  3. Which Python library is most commonly used for data visualization?

    Answer: Matplotlib

    Matplotlib is the foundational Python visualization library used to create line charts, bar charts, scatter plots, and more.

  4. What does 'vectorization' mean in the context of pandas or NumPy?

    Answer: Applying operations to entire arrays without explicit Python loops

    Vectorization applies operations element-wise across arrays using optimized C-level code, making computations significantly faster than Python loops.

  5. What is the purpose of Excel's SUMIF function?

    Answer: Sums cells in a range that meet a specified condition

    SUMIF adds the values in a range only for rows where a specified condition is true.

  6. What does the pandas .drop_duplicates() method do?

    Answer: Removes rows that are exact duplicates of other rows

    drop_duplicates() removes rows where all (or specified) column values are identical to a previous row, keeping only unique records.