DA Data Analysis Tools and Programming 1 — Questions and Answers
Question 1: Which Python library is primarily used for data manipulation and analysis?
- NumPy
- Matplotlib
- Pandas (Correct answer)
- SciPy
Correct answer: Pandas
Pandas provides the DataFrame structure and a rich set of functions for data cleaning, transformation, and analysis in Python.
Question 2: What does the pandas function df.describe() return?
- The column data types
- Summary statistics (count, mean, std, min, max, percentiles) for numeric columns (Correct answer)
- The first five rows of the DataFrame
- The number of missing values per column
Correct answer: Summary statistics (count, mean, std, min, max, percentiles) for numeric columns
df.describe() generates descriptive statistics including count, mean, standard deviation, and quartile values for numeric columns.
Question 3: In Excel, which function is used to look up a value in a table and return a corresponding value from another column?
- SUMIF
- COUNTIF
- VLOOKUP (Correct answer)
- INDEX
Correct answer: VLOOKUP
VLOOKUP searches the first column of a range for a value and returns a result from a specified column in the same row.
Question 4: What is a pivot table used for in Excel or data analysis?
- Generating random sample data
- Summarizing, aggregating, and reorganizing data interactively (Correct answer)
- Writing macros for automation
- Formatting cells conditionally
Correct answer: Summarizing, aggregating, and reorganizing data interactively
Pivot tables let analysts quickly summarize large datasets by grouping and aggregating values across rows and columns.
Question 5: What is R primarily used for in data analysis?
- Web development
- Statistical computing and data visualization (Correct answer)
- Database administration
- Network monitoring
Correct answer: Statistical computing and data visualization
R is a programming language designed for statistical analysis, data manipulation, and producing high-quality visualizations.
Question 6: What does the Python function len() return when applied to a pandas DataFrame?
- Number of columns
- Number of non-null values
- Number of rows (Correct answer)
- Memory usage in bytes
Correct answer: Number of rows
len(df) returns the number of rows in a pandas DataFrame, equivalent to df.shape[0].
DA Data Analysis Tools and Programming 1
Which Python library is primarily used for data manipulation and analysis?